Seeking input

[Saphroneth]

I've see this claim a few times, but in my mind the evidence does not support it, at least in Burnsides case.

The evidence is that every subordinate, and indeed all the Confederates, gave times that were not in keeping with Burnside. I'd be glad to go into the detail for this one.

This isn't from Marvel, this is just that Burnside rejects the times given by everyone else.



Here is my understanding of the actual timings relevant to the bridge:



Before 7AM - Cox moves Rodman's division away from the Lower Bridge to find a ford (Rodman's being the only division at the bridge) at Burnside's orders, leaving just the 11th CT.
It appears to be that the ford they were originally meant to cross (not Snavely's, the "Farm Ford" which is much closer to the lower bridge) was considered impassible because it was defended. It is passed by a brigade once the crossing is unopposed.

Before 7AM - McClellan sends warning order to Burnside, telling him to be ready to attack/move his force to the bridge (which is basically a reiteration of the orders from the 16th) but not to attack until ordered (This is Cox's account of what Burnside told him)

8AM - McClellan sends an order to Burnside to attack immediately (Lt James Wilson carried this)
Around 8AM: The 11th CT drives in Rebel pickets on the eastern bank of the Antietam at the lower bridge.

8:30 AM - Hooker and Mansfield are known to have gone down

Before 9AM: Crook's brigade of 9th Corps were ordered forwards, but got lost
Before 9AM: Cox is ordering Sturgis' division forwards

9AM: Burnside orders assault against the Lower Bridge, only one regiment is present (11th CT) and they are repulsed
9AM: Sturgis starts moving to the Lower Bridge

9:10 AM: McClellan reiterates the 8AM order to Burnside (Col Sackett carried this). This is the order we have, but the statement it gives of the situation on the right is not in keeping with 9:10 (instead it is in keeping with 8AM).

Around 9:10: the West Woods and Sunken Road fights begin (Sedgwick and French), beginning a 90 minute long crisis on the Federal right; McClellan will move over there to supervise


10AM: 1st regiment of Nagle's brigade (2nd MD) charge the Lower Bridge and are repulsed
10:30 AM: 2nd regiment of Nagle's brigade (6th NH) charge the Lower Bridge and are repulsed, Sturgis decides to push artillery onto the heights to gain control of the bridge


11AM: artillery begins bombarding the Confederates defending the lower bridge, and they pull out their guns once this happens

11:30 AM: Toombs pulls out his infantry from the Lower Bridge as well, leaving just a few pickets

Around noon, order of events not quite clear: McClellan returns to his HQ at the middle bridge, sends a fourth and very emphatic order to attack to Burnside (carried by Colonel Key) with a sealed order relieving Burnside and placing Morell in charge of 9th Corps in the case he doesn't follow it.
12:30 PM: Ferrero gets two regiments to charge and takes the bridge



Everyone else's timings support this (including Cox's AAR, though not Cox postwar), except Burnside, who states that he got the order to attack only at 10AM and that he then advanced the 11th CT. McClellan then accepts Burnside's timings, but he'd previously written to his wife about how if he gave Burnside an honest assessment it'd make Burnside a "mortal enemy".

 

[Saphroneth]

I'll have to check Marvel's source on it, from my memory its portrayed as having reached Burnside by 12 and that Burnside was in position to easily receive it.

Though of course if the order was sent around 9AM and it didn't reach Burnside for hours, that's way longer than it should have taken - thus the problem.

 

[Old Burn]

Though of course if the order was sent around 9AM and it didn't reach Burnside for hours, that's way longer than it should have taken - thus the problem.

I went back and took a look at Marvel's source; it seems that that gap in time comes from Jacob Cox's Military Reminiscences. Burnside was with Mclellan the morning after south Mountain, and according to Mac in Own Story he gave him a verbal order to move forward. Apparently, he also sent a dispatch to Burnside around 12:30 on the 15th to inquire why he hadn't moved yet, I can't seem to find Burnsides reply to it, but it's worth noting that when they met later that day in person Mclellan failed to bring up Burnsides supposed tardiness.

 

[Old Burn]

The evidence is that every subordinate, and indeed all the Confederates, gave times that were not in keeping with Burnside. I'd be glad to go into the detail for this one.

This isn't from Marvel, this is just that Burnside rejects the times given by everyone else.



Here is my understanding of the actual timings relevant to the bridge:



Before 7AM - Cox moves Rodman's division away from the Lower Bridge to find a ford (Rodman's being the only division at the bridge) at Burnside's orders, leaving just the 11th CT.
It appears to be that the ford they were originally meant to cross (not Snavely's, the "Farm Ford" which is much closer to the lower bridge) was considered impassible because it was defended. It is passed by a brigade once the crossing is unopposed.

Before 7AM - McClellan sends warning order to Burnside, telling him to be ready to attack/move his force to the bridge (which is basically a reiteration of the orders from the 16th) but not to attack until ordered (This is Cox's account of what Burnside told him)

8AM - McClellan sends an order to Burnside to attack immediately (Lt James Wilson carried this)
Around 8AM: The 11th CT drives in Rebel pickets on the eastern bank of the Antietam at the lower bridge.

8:30 AM - Hooker and Mansfield are known to have gone down

Before 9AM: Crook's brigade of 9th Corps were ordered forwards, but got lost
Before 9AM: Cox is ordering Sturgis' division forwards

9AM: Burnside orders assault against the Lower Bridge, only one regiment is present (11th CT) and they are repulsed
9AM: Sturgis starts moving to the Lower Bridge

9:10 AM: McClellan reiterates the 8AM order to Burnside (Col Sackett carried this). This is the order we have, but the statement it gives of the situation on the right is not in keeping with 9:10 (instead it is in keeping with 8AM).

Around 9:10: the West Woods and Sunken Road fights begin (Sedgwick and French), beginning a 90 minute long crisis on the Federal right; McClellan will move over there to supervise


10AM: 1st regiment of Nagle's brigade (2nd MD) charge the Lower Bridge and are repulsed
10:30 AM: 2nd regiment of Nagle's brigade (6th NH) charge the Lower Bridge and are repulsed, Sturgis decides to push artillery onto the heights to gain control of the bridge


11AM: artillery begins bombarding the Confederates defending the lower bridge, and they pull out their guns once this happens

11:30 AM: Toombs pulls out his infantry from the Lower Bridge as well, leaving just a few pickets

Around noon, order of events not quite clear: McClellan returns to his HQ at the middle bridge, sends a fourth and very emphatic order to attack to Burnside (carried by Colonel Key) with a sealed order relieving Burnside and placing Morell in charge of 9th Corps in the case he doesn't follow it.
12:30 PM: Ferrero gets two regiments to charge and takes the bridge



Everyone else's timings support this (including Cox's AAR, though not Cox postwar), except Burnside, who states that he got the order to attack only at 10AM and that he then advanced the 11th CT. McClellan then accepts Burnside's timings, but he'd previously written to his wife about how if he gave Burnside an honest assessment it'd make Burnside a "mortal enemy".

A couple of things to note:
1. I don't find the claim that Wilson delivered the order to be creditable. If that was the case, I don't know how it would be possible for Mclellan to mistakenly put 10 AM in his AAR.
2. I don't buy Mclellan's "mortal enemy" comment. In the past few days, he had removed Burnside from wing command and sent him a formal reprimand about moving his troops to slowly on the 16th (Mclellan claimed Burnside was supposed to have his troops in position by noon on the 16th, when in fact he didn't even give him that order until after that time). Marvel describes a series of other "serial affronts" to Burnside by Mclellan during the campaign, so it seems unlikely that he had suddenly decided to tread carefully with him.
3. The story that key was caring an order to relieve Burnside is shaky at best. Mac never mentions it once, even when he's actively trying to discredit Burnsides performance in Own Story. Key never mentioned either, it was only mentioned around 30 years later in Biddle's recollections.

I'm actually willing to accept the fact that Burnsides timing of receiving the order was incorrect, but I don't think he did it on purpose, I think he made a genuine mistake. I do however think Mclellan later created the 8 AM attack order, and that the order carried by Sackett probably reached Burnside around nine. He then executed it to the best of his ability, carrying what even Mclellan admitted was a very difficult objective. He probably would have won the day too if Mclellan had sent the support that was promised in his earlier orders.

 

[67th Tigers]

About five years ago I started writing this blog post. He is a section, with grammar errors, hanging sentences etc.:

McClellan's Plans

One of the major problems with analysing McClellan's plans is that he obviously "ret-conned" his plans after the battle. He appears to have done this to save Burnside. On 29th September McClellan wrote to his wife:

"I have been hard at work all day upon a preliminary report of the recent battles, and find that, in order to arrive at anything like the truth, I must tomorrow take all my aides to the ground and talk with them there. I would really prefer fighting three battles to writing the report of one. You can hardly imagine the difficulties of such a task. You are necessarily combating the amour propre, the vanity of every officer concerned when you say one word in commendation of anybody else. Each one is firmly convinced of the fact that no one but he had anything to do with the result, every commander of a brigade becomes firmly convinced that he fought the whole battle & that he arranged the general plan, of which he knew simply nothing."

"I ought to rap Burnside very severely, and probably will; yet I hate to do it. He is very slow; is not fit to command more than a regiment. If I rap him as he deserves he will be my mortal enemy hereafter. If I do not praise him as he thinks he deserves, and as I know he does not, he will be at least a very lukewarm friend. I mention this merely as an instance that you will comprehend..."

This is a very revealing letter. McClellan would not submit his report until 15th October, 17 days later. When he submitted his report he did not "rap" Burnside, but rather accepted Burnside's report, which was submitted on the 30th September (i.e. the day after the above to Mrs. McClellan). Burnside's subordinate, Cox, submitted his report on 23rd September. Cox's subordinates had written theirs during the previous few days. Burnside had taken a week to extract Cox's report and rewrite it for himself. Amongst the changes he made was the start time – Burnside invented a 1000 order, which Moe D'Aoust has analysed in depth.

McClellan defended Burnside despite the fact that their friendship had already been broken, and it was broken when Burnside prepared charges of treason against Fitz-John Porter in early September

Before moving further, it is worth considering what orders we know Burnside received, and what was happening in sequence:

• McClellan says he sent Burnside an order "early in the morning" "to form his troops, and hold them in readiness to assault the bridge in his front, and await further orders". Cox says he received this order from Burnside "around 7 o'clock", which means it was sent considerably before 0700, and probably before 0630. Indeed, this may be a dawn order.
• At around 0700 an artillery duel between Benjamin's and Durell's batteries on the Federal side, and Eubank's rebel battery commenced. Benning, commanding the rebel defenders, notes that Eubank opened on enemy infantry forming in the woods, and that the Federals soon won the duel, allowing for the driving in of his pickets at 0900 by the advance of the 11th Connecticut.
• In his report Burnside says he didn't even receive the order to position to attack the bridge until after the termination of this artillery duel, meaning he'd put that order forward ca. two hours.
• McClellan says he sent Lt Wilson with the attack order at 0800. Wilson's diary records he did exactly that. Burnside will claim not receiving it until 1000.
• McClellan says (ca. 0900) he sent an aide to determine whether the bridge had been carried, and his aide returned saying it hadn't.
• At 0900 the 11th Connecticut under Henry Kingsbury makes an attack, and is repulsed in about 30 minutes of shooting with 139 casualties out of 440 present(as an aside, the 11th Conn was from Rodman's division, and was left to guard a battery. Their brigadier was annoyed when he sent back for them).
• Simultaneously, George Crook's brigade was ordered to attack. Capt Christ of Cox's staff carried the order, but did not know the way to the bridge. Crook's brigade was thrashing around in the woods and simply never found the bridge, except for half of the 28th Ohio who were sent ahead as a recce, popped out of the woods 350 yds north of the bridge. They sent back guides who also got lost.
• McClellan says he sent the same aide back with a positive order to assault immediately. This may be the 0910 order, which analysis by D'Aoust clearly shows was a repeat of the 0800 order.
• McClellan says he then sent Col Sackett, his inspector-general, to Burnside at 1000. Sackett was ordered to make sure Burnside attacked and remain with him to ensure he did attack. Sackett later wrote that Burnside told him that this was the third or fourth attack order he'd received.
• At 1030, Nagle's brigade makes an attack and is repulsed.
• At around 1300 Colonel Key is sent to Burnside. In his pocket is an order relieving Burnside of command, and appointing General Morell to assume command. He and Sackett persuade Burnside to take personal command of the situation, but he soon returns with news that

16th September and Pre-dawn Orders

McClellan met Burnside on the morning of the 16th September and spent around an hour with him, the longest he spent with any of his subordinates. As the second highest ranking general in the army, Burnside would take over if McClellan went down. Burnside's AAR says:

"On the next day (16th) I was ordered by the general commanding to place our batteries on the crests of the hills near the bridge, the infantry being moved forward in support, and the commands were immediately placed in their proper positions."

It is worth noting that Burnside failed in this. His gunline (see below) was well south of the bridge, and faced south, not west. Burnside was placing his forces not to attack the bridge, but rather to repel an assault from the south. As to Cox, according to his Military Memoirs he was still a division commander. He wrote that he saw Burnside on the afternoon of the 16th, and that Burnside had decided that he would not command 9th Corps because it offended his pride, and assigned Cox to do it. Cox's memoirs make it clear that the Kanawha division ceased to function as a division, with Scammon's brigade attached to Rodman's division and Crook's brigade to Sturgis. Cox himself notes that all he knew about the plan was what Burnside told him; that they were a diversion. It should not be thought that Burnside had abrogated command; the reports of the division commander note that they continued to receive their orders from Burnside, and Cox's assessment that he was effective second-in-command is correct.

Accompanying McClellan were his artillery chief (BG Hunt), his engineer chief (Capt Duane) and Col Colburn, ADC. Around 1500, three hours after his previous departure, Capt Duane returned with 3 subalterns to examine the stream for fords. He was likely expecting to find 9th Corps had advanced skirmishers to the creek to allow him and his staff to work. Alas, he was disappointed; not a single man had moved in the intervening three hours.


Dawn – 0800

9th Corps did not reach their start line on the 16th. The rebel piquets are still on the east side of the Antietam, and the engineers have not been able to get near to the creek to look for a ford. The only troops on the bluffs are Rodman's 7 regiments and 5 of the division's batteries. George Crook's brigade of 3 regiments is apparently nearby (although the map appears to place him nearer than he was, as the brigade camped on the road 400 yards east of where the map places them).

The Carman maps show Rodman's division marching away from the bridge at 0630-0730, leaving no units at the bridge at all. They moved SE behind the hills the gunline was on. Harland's report places his movement (the second brigade to move) was at 0700.

As Harland's brigade move off, Eubank's battery opened on them (see the report of the 4th RI's Curtis). This sparked Benjamin's battery to open fire on Eubank, at a time he gives as "early".

When this artillery duel opened at ca. 0700, Cox's own memoirs place him as having his breakfast

First attack order: Lt Wilson carries

0800 – 1000

On finishing their retrograde, Rodman's division moved off to protect Duane's search for a ford "shortly afterwards" (Harland's report) their movement SE. Curtis (4th RI) reported an interval of "about an hour" between the SE retrograde, and the expedition starting. Allowing for time for the initial retrograde, this would indicate Rodman's division marched SW on the search for the ford at ca. 0800 – 0830. Notably, the Carman maps place this event at ca. 1030.

Rodman left one regiment behind to cover his front; the 11th Connecticut under Lt Col Kingsbury.

In roughly this same time period, Burnside ordered the initial attack. His orders went to George Crook's brigade and the 11th Connecticut. Kingsbury of the 11th Connecticut knew where the bridge was and promptly advanced on it. George Crook had never seen the bridge, or even Antietam Creek, and didn't even know there was a creek with a bridge he was expected to assault. Captain Christ, delivering the order, was of little help. Crook sent two recce parties forward to try and find the creek. Two coys of the 11th Ohio head west and climbed the hill overlooking the Antietam. Five coys of the 28th Ohio headed northwest and came out "round the bend" from the bridge, and couldn't see it.

The skirmishers of the 11th Ohio, and the advance of the 11th Connecticut drove in the rebel skirmishers east of the creek. The 11th Connecticut then attempted to carry the bridge on their own. Rebel reports agree the charge of the 11th Connecticut was at 0900 (The Carman map both concurs with a ca. 0900 charge but has the 11th Ct still fighting at 1000 in an attempt to reconcile the contradictions). The attempt lasted less than half an hour, with 139 members of the 11th Connecticut hit, including Kingsbury.

George Crook still hadn't found the bridge, and by his own admission didn't find it until Sturgis' Division had carried it at 1300. We shall ignore Crook's brigade from now on.

Along with an order to Crook and Kingsbury to attack the brigade, an order was sent back for Sturgis to march his division to the bridge. His two batteries were engaged on the bluffs looking NW (away from the bridge), and he marched his 8 regiments towards the bridge with the batteries following. Ferrero give a time of 0900 in his report of starting this movement, and whilst this is the only timing, it is self-consistent. The Carman map agrees with this timing.

At the same time (recorded as 0900 by Gerhardt of the 46th NY) Willcox's Division broke camp and moved to relieve Sturgis.

1000 – 1100

By 1000 hrs only the 11th Connecticut had attacked the bridge. Crook's brigade was still lost. Sturgis' Division was deployed. They followed the fenced road and Ferrero's brigade was deployed in line in the cornfield to the left of the track, and Nagle's brigade to the right. Nagle's brigade "became engaged" around 1000 hrs according to Capt. Bosbyshell of the 48th Pennsylvania, although the 48th Pa itself only became engaged around 1100. (ref)

At ca. 1000, the 2nd Maryland and 6th New Hampshire of Nagle's brigade were in line. They made two consecutive charges at the bridge. Both were staggered by the weight of fire put on them, and both halted in front of the bridge to exchange fire. As one can expect, standing in the open with 8 artillery pieces and two infantry regiments firing down on them, they were slaughters. The 2nd Maryland charged first, at 1000, and reached the post and rail fence that barred their movement. They halted there, and started to smash it down, but soon went to ground. The 6th New Hampshire charged next, at ca. 1030, and the exact same thing happened.

Around 1100 hrs the 48th Pennsylvania, who had reached the heights overlooking the bridge, had 4 coys (the most that could be deployed) open fire to cover the withdrawal of the two regiments pinned down behind the fence.

The attack was not successful. Neither Burnside, nor any other officer had thought to try and suppress the two rebel batteries covering the bridge (Richardson's and Brown's). They rained down a storm of canister and case that made the approach a slaughter. The attack was not pressed, which limited the slaughter. The chargers were hung up on the fences that lined the track.

1100 – 1300

By 1100, Nagle's slapdash attempt to simply charge the bridge had failed. Sturgis decided to do things properly.

Around this time, Lt Glassie of Simmond's Battery managed to get a 10 pdr Parrott and a light 12 pdr howitzer onto the high ground occupied by part of the 48th Pa. It is a great shame that he opened fire on the infantry in the scrub, and did not suppress the two batteries dominating the bridge.

Also around this time, Capt Clark however moved his regular battery to ca. 700 yards from Brown's battery and opened fire. Capt Durell moved his Pennsylvania battery onto the heights with the 48th Pa (and Glassie's section) and opened fire at Richardson's battery, silencing it (as described in the battery history).

Hence, from ca. 1100 hours 12 Federal guns engaged the 8 rebel guns, and they took their toll. Now both rebel batteries which had been so problematic were under heavy fire. Toombs, commanding the defenders, decided that this, and the threat of Rodman crossing the ford (which he had not done) made his position untenable. He ordered a withdrawal. The timing of this order would appear to be around 1100, or slightly thereafter – Toombs stated it was two hours after Eubank's battery was forced to withdraw (around 0900).

Chaos was reigning in Ferrero's dysfunctional brigade. Hartranft, the German colonel of the 51st Pa and Col. Potter of the 51st New York were in near open mutiny, refusing to follow Ferrero's orders. The colonel of the 21st New York also considered orders from his brigadier to be "suggestions". Ferrero's own regiment, the 35th Massachusetts, had to be kept away from the fighting, being worse than useless and having put a panicked volley into the back of the 51st Pa at South Mountain.

Sturgis issued orders (given to him by Burnside) for Ferrero to assault the bridge, and the orders were carried by Lt Hudson. Ferrero disputed the order and started engaging in a back and forth discussion with Sturgis about the wisdom of the attack. After maybe 30 mins of back and forth via Hudson, Sturgis bluntly told Ferrero that it was a peremptory order from Burnside. Since his CO's were refusing to obey him, he appealed directly to the soldiers, leading to him promising whiskey.

At ca. 1230, after spending maybe half an hour posting the 51st Pa etc., they charged, almost unopposed, across the bridge. The defenders had bugged out, leaving only a skirmish party.

At 1300 the 51st Pa, 51st NY and a section of Durell's battery sent to give fire support, established themselves across the creek, and the bridge was finally in Federal hands. They did not advance onto the heights, but instead stopped on the banks of the creek, and started brewing coffee. It would take a considerable amount of time to get troops onto the heights proper.

Given the timings, Burnside probably ordered Sturgis to assault again with his other brigade between 1100 and 1130.

Summary of the Tactical Affair

Burnside did not have forces in place to attack the bridge in the morning, despite orders. His only division near the bridge, Rodman's, was diverted to look for a ford. Whilst moving, Rodman was shelled from a height south of the bridge, and counterbattery fire eventually silenced the battery.

 

[Old Burn]

About five years ago I started writing this blog post. He is a section, with grammar errors, hanging sentences etc.:

McClellan's Plans

One of the major problems with analysing McClellan's plans is that he obviously "ret-conned" his plans after the battle. He appears to have done this to save Burnside. On 29th September McClellan wrote to his wife:

"I have been hard at work all day upon a preliminary report of the recent battles, and find that, in order to arrive at anything like the truth, I must tomorrow take all my aides to the ground and talk with them there. I would really prefer fighting three battles to writing the report of one. You can hardly imagine the difficulties of such a task. You are necessarily combating the amour propre, the vanity of every officer concerned when you say one word in commendation of anybody else. Each one is firmly convinced of the fact that no one but he had anything to do with the result, every commander of a brigade becomes firmly convinced that he fought the whole battle & that he arranged the general plan, of which he knew simply nothing."

"I ought to rap Burnside very severely, and probably will; yet I hate to do it. He is very slow; is not fit to command more than a regiment. If I rap him as he deserves he will be my mortal enemy hereafter. If I do not praise him as he thinks he deserves, and as I know he does not, he will be at least a very lukewarm friend. I mention this merely as an instance that you will comprehend..."

This is a very revealing letter. McClellan would not submit his report until 15th October, 17 days later. When he submitted his report he did not "rap" Burnside, but rather accepted Burnside's report, which was submitted on the 30th September (i.e. the day after the above to Mrs. McClellan). Burnside's subordinate, Cox, submitted his report on 23rd September. Cox's subordinates had written theirs during the previous few days. Burnside had taken a week to extract Cox's report and rewrite it for himself. Amongst the changes he made was the start time – Burnside invented a 1000 order, which Moe D'Aoust has analysed in depth.

McClellan defended Burnside despite the fact that their friendship had already been broken, and it was broken when Burnside prepared charges of treason against Fitz-John Porter in early September

Before moving further, it is worth considering what orders we know Burnside received, and what was happening in sequence:

• McClellan says he sent Burnside an order "early in the morning" "to form his troops, and hold them in readiness to assault the bridge in his front, and await further orders". Cox says he received this order from Burnside "around 7 o'clock", which means it was sent considerably before 0700, and probably before 0630. Indeed, this may be a dawn order.
• At around 0700 an artillery duel between Benjamin's and Durell's batteries on the Federal side, and Eubank's rebel battery commenced. Benning, commanding the rebel defenders, notes that Eubank opened on enemy infantry forming in the woods, and that the Federals soon won the duel, allowing for the driving in of his pickets at 0900 by the advance of the 11th Connecticut.
• In his report Burnside says he didn't even receive the order to position to attack the bridge until after the termination of this artillery duel, meaning he'd put that order forward ca. two hours.
• McClellan says he sent Lt Wilson with the attack order at 0800. Wilson's diary records he did exactly that. Burnside will claim not receiving it until 1000.
• McClellan says (ca. 0900) he sent an aide to determine whether the bridge had been carried, and his aide returned saying it hadn't.
• At 0900 the 11th Connecticut under Henry Kingsbury makes an attack, and is repulsed in about 30 minutes of shooting with 139 casualties out of 440 present(as an aside, the 11th Conn was from Rodman's division, and was left to guard a battery. Their brigadier was annoyed when he sent back for them).
• Simultaneously, George Crook's brigade was ordered to attack. Capt Christ of Cox's staff carried the order, but did not know the way to the bridge. Crook's brigade was thrashing around in the woods and simply never found the bridge, except for half of the 28th Ohio who were sent ahead as a recce, popped out of the woods 350 yds north of the bridge. They sent back guides who also got lost.
• McClellan says he sent the same aide back with a positive order to assault immediately. This may be the 0910 order, which analysis by D'Aoust clearly shows was a repeat of the 0800 order.
• McClellan says he then sent Col Sackett, his inspector-general, to Burnside at 1000. Sackett was ordered to make sure Burnside attacked and remain with him to ensure he did attack. Sackett later wrote that Burnside told him that this was the third or fourth attack order he'd received.
• At 1030, Nagle's brigade makes an attack and is repulsed.
• At around 1300 Colonel Key is sent to Burnside. In his pocket is an order relieving Burnside of command, and appointing General Morell to assume command. He and Sackett persuade Burnside to take personal command of the situation, but he soon returns with news that

16th September and Pre-dawn Orders

McClellan met Burnside on the morning of the 16th September and spent around an hour with him, the longest he spent with any of his subordinates. As the second highest ranking general in the army, Burnside would take over if McClellan went down. Burnside's AAR says:

"On the next day (16th) I was ordered by the general commanding to place our batteries on the crests of the hills near the bridge, the infantry being moved forward in support, and the commands were immediately placed in their proper positions."

It is worth noting that Burnside failed in this. His gunline (see below) was well south of the bridge, and faced south, not west. Burnside was placing his forces not to attack the bridge, but rather to repel an assault from the south. As to Cox, according to his Military Memoirs he was still a division commander. He wrote that he saw Burnside on the afternoon of the 16th, and that Burnside had decided that he would not command 9th Corps because it offended his pride, and assigned Cox to do it. Cox's memoirs make it clear that the Kanawha division ceased to function as a division, with Scammon's brigade attached to Rodman's division and Crook's brigade to Sturgis. Cox himself notes that all he knew about the plan was what Burnside told him; that they were a diversion. It should not be thought that Burnside had abrogated command; the reports of the division commander note that they continued to receive their orders from Burnside, and Cox's assessment that he was effective second-in-command is correct.

Accompanying McClellan were his artillery chief (BG Hunt), his engineer chief (Capt Duane) and Col Colburn, ADC. Around 1500, three hours after his previous departure, Capt Duane returned with 3 subalterns to examine the stream for fords. He was likely expecting to find 9th Corps had advanced skirmishers to the creek to allow him and his staff to work. Alas, he was disappointed; not a single man had moved in the intervening three hours.


Dawn – 0800

9th Corps did not reach their start line on the 16th. The rebel piquets are still on the east side of the Antietam, and the engineers have not been able to get near to the creek to look for a ford. The only troops on the bluffs are Rodman's 7 regiments and 5 of the division's batteries. George Crook's brigade of 3 regiments is apparently nearby (although the map appears to place him nearer than he was, as the brigade camped on the road 400 yards east of where the map places them).

The Carman maps show Rodman's division marching away from the bridge at 0630-0730, leaving no units at the bridge at all. They moved SE behind the hills the gunline was on. Harland's report places his movement (the second brigade to move) was at 0700.

As Harland's brigade move off, Eubank's battery opened on them (see the report of the 4th RI's Curtis). This sparked Benjamin's battery to open fire on Eubank, at a time he gives as "early".

View attachment 462716

When this artillery duel opened at ca. 0700, Cox's own memoirs place him as having his breakfast

First attack order: Lt Wilson carries

0800 – 1000

On finishing their retrograde, Rodman's division moved off to protect Duane's search for a ford "shortly afterwards" (Harland's report) their movement SE. Curtis (4th RI) reported an interval of "about an hour" between the SE retrograde, and the expedition starting. Allowing for time for the initial retrograde, this would indicate Rodman's division marched SW on the search for the ford at ca. 0800 – 0830. Notably, the Carman maps place this event at ca. 1030.

Rodman left one regiment behind to cover his front; the 11th Connecticut under Lt Col Kingsbury.

In roughly this same time period, Burnside ordered the initial attack. His orders went to George Crook's brigade and the 11th Connecticut. Kingsbury of the 11th Connecticut knew where the bridge was and promptly advanced on it. George Crook had never seen the bridge, or even Antietam Creek, and didn't even know there was a creek with a bridge he was expected to assault. Captain Christ, delivering the order, was of little help. Crook sent two recce parties forward to try and find the creek. Two coys of the 11th Ohio head west and climbed the hill overlooking the Antietam. Five coys of the 28th Ohio headed northwest and came out "round the bend" from the bridge, and couldn't see it.

The skirmishers of the 11th Ohio, and the advance of the 11th Connecticut drove in the rebel skirmishers east of the creek. The 11th Connecticut then attempted to carry the bridge on their own. Rebel reports agree the charge of the 11th Connecticut was at 0900 (The Carman map both concurs with a ca. 0900 charge but has the 11th Ct still fighting at 1000 in an attempt to reconcile the contradictions). The attempt lasted less than half an hour, with 139 members of the 11th Connecticut hit, including Kingsbury.

George Crook still hadn't found the bridge, and by his own admission didn't find it until Sturgis' Division had carried it at 1300. We shall ignore Crook's brigade from now on.

Along with an order to Crook and Kingsbury to attack the brigade, an order was sent back for Sturgis to march his division to the bridge. His two batteries were engaged on the bluffs looking NW (away from the bridge), and he marched his 8 regiments towards the bridge with the batteries following. Ferrero give a time of 0900 in his report of starting this movement, and whilst this is the only timing, it is self-consistent. The Carman map agrees with this timing.

At the same time (recorded as 0900 by Gerhardt of the 46th NY) Willcox's Division broke camp and moved to relieve Sturgis.

1000 – 1100

By 1000 hrs only the 11th Connecticut had attacked the bridge. Crook's brigade was still lost. Sturgis' Division was deployed. They followed the fenced road and Ferrero's brigade was deployed in line in the cornfield to the left of the track, and Nagle's brigade to the right. Nagle's brigade "became engaged" around 1000 hrs according to Capt. Bosbyshell of the 48th Pennsylvania, although the 48th Pa itself only became engaged around 1100. (ref)

At ca. 1000, the 2nd Maryland and 6th New Hampshire of Nagle's brigade were in line. They made two consecutive charges at the bridge. Both were staggered by the weight of fire put on them, and both halted in front of the bridge to exchange fire. As one can expect, standing in the open with 8 artillery pieces and two infantry regiments firing down on them, they were slaughters. The 2nd Maryland charged first, at 1000, and reached the post and rail fence that barred their movement. They halted there, and started to smash it down, but soon went to ground. The 6th New Hampshire charged next, at ca. 1030, and the exact same thing happened.

Around 1100 hrs the 48th Pennsylvania, who had reached the heights overlooking the bridge, had 4 coys (the most that could be deployed) open fire to cover the withdrawal of the two regiments pinned down behind the fence.

The attack was not successful. Neither Burnside, nor any other officer had thought to try and suppress the two rebel batteries covering the bridge (Richardson's and Brown's). They rained down a storm of canister and case that made the approach a slaughter. The attack was not pressed, which limited the slaughter. The chargers were hung up on the fences that lined the track.

1100 – 1300

By 1100, Nagle's slapdash attempt to simply charge the bridge had failed. Sturgis decided to do things properly.

Around this time, Lt Glassie of Simmond's Battery managed to get a 10 pdr Parrott and a light 12 pdr howitzer onto the high ground occupied by part of the 48th Pa. It is a great shame that he opened fire on the infantry in the scrub, and did not suppress the two batteries dominating the bridge.

Also around this time, Capt Clark however moved his regular battery to ca. 700 yards from Brown's battery and opened fire. Capt Durell moved his Pennsylvania battery onto the heights with the 48th Pa (and Glassie's section) and opened fire at Richardson's battery, silencing it (as described in the battery history).

Hence, from ca. 1100 hours 12 Federal guns engaged the 8 rebel guns, and they took their toll. Now both rebel batteries which had been so problematic were under heavy fire. Toombs, commanding the defenders, decided that this, and the threat of Rodman crossing the ford (which he had not done) made his position untenable. He ordered a withdrawal. The timing of this order would appear to be around 1100, or slightly thereafter – Toombs stated it was two hours after Eubank's battery was forced to withdraw (around 0900).

Chaos was reigning in Ferrero's dysfunctional brigade. Hartranft, the German colonel of the 51st Pa and Col. Potter of the 51st New York were in near open mutiny, refusing to follow Ferrero's orders. The colonel of the 21st New York also considered orders from his brigadier to be "suggestions". Ferrero's own regiment, the 35th Massachusetts, had to be kept away from the fighting, being worse than useless and having put a panicked volley into the back of the 51st Pa at South Mountain.

Sturgis issued orders (given to him by Burnside) for Ferrero to assault the bridge, and the orders were carried by Lt Hudson. Ferrero disputed the order and started engaging in a back and forth discussion with Sturgis about the wisdom of the attack. After maybe 30 mins of back and forth via Hudson, Sturgis bluntly told Ferrero that it was a peremptory order from Burnside. Since his CO's were refusing to obey him, he appealed directly to the soldiers, leading to him promising whiskey.

At ca. 1230, after spending maybe half an hour posting the 51st Pa etc., they charged, almost unopposed, across the bridge. The defenders had bugged out, leaving only a skirmish party.

At 1300 the 51st Pa, 51st NY and a section of Durell's battery sent to give fire support, established themselves across the creek, and the bridge was finally in Federal hands. They did not advance onto the heights, but instead stopped on the banks of the creek, and started brewing coffee. It would take a considerable amount of time to get troops onto the heights proper.

Given the timings, Burnside probably ordered Sturgis to assault again with his other brigade between 1100 and 1130.

Summary of the Tactical Affair

Burnside did not have forces in place to attack the bridge in the morning, despite orders. His only division near the bridge, Rodman's, was diverted to look for a ford. Whilst moving, Rodman was shelled from a height south of the bridge, and counterbattery fire eventually silenced the battery.

As I stated above, I don't really buy Mclellan's "mortal enemy" comments. Over the past few days, he had basically done everything in his power to strain their friendship, Marvel describes Mclellan as serially affronting Burnside during the Maryland campaign, so the idea that he had suddenly decided to tread carefully with him is strange. His comments about Burnside getting angry about not receiving the credit he feels he deserves also doesn't seem to fit. Mclellan barely mentioned Burnside in his report of the battle of south mountain, despite the fact that Burnside basically directed it, and yet he never argued with Mclellan over that.

Was it Burnside who "prepared the charges of treason" against Porter? To my knowledge, all he did was forward Porter's telegram's to Washington, I believe he even testified in Porter's defense at his court martial. To me, it seems that Burnside and Mclellan's friendship was broken when Lincoln started offering Burnside the command of the army of the Potomac. William Marvel makes a good case in his biography of Burnside that Mac was jealous of his old friend, which might have been why he basically failed to mention Burnsides contributions to the victory at south mountain.

Although I do think Burnside was wrong about not receiving an order to assault the bridge until 10, I don't think he was intentionally engaging in a cover up of that fact, I think he genuinely just got the time wrong. This is the same man who accepted the blame for the battle of Fredericksburg when he really didn't have to, it would be out of character for him to lie about this order. I also don't find the evidence of the Wilson order to be that convincing. Wilson's diary was never found, the only evidence we have is a letter where he references delivering the order, and at that point he may have just been going along with version of events in Mclellan's Own Story.
Do you have a source that says Burnside wouldn't accept command of the IX corps because of his pride? From my understanding, he was just under the belief that the suspension of the wing structure was temporary, and that he would be returned to that position after the battle.

The story that key was caring an order to relieve Burnside is shaky at best. Mac never mentions it once, even when he's actively trying to discredit Burnsides performance in Own Story. Key never mentioned either, it was only mentioned around 30 years later in Biddle's recollections.

I have to say I'm kind of confused as to what your claim is, are you saying that Burnside did receive an 8 AM order and then did not attacl because his units were not properly in place?

 

[Saphroneth]

Although I do think Burnside was wrong about not receiving an order to assault the bridge until 10, I don't think he was intentionally engaging in a cover up of that fact, I think he genuinely just got the time wrong.

But all of the subordinate reports (which had been written - subordinate reports are collated and fed up the chain of command, so the upper echelons write their reports with all the information in hand) give the correct (earlier) timings. Burnside gives times two hours or so later than everyone else involved, and he does so as a conscious change.

 

[Old Burn]

But all of the subordinate reports (which had been written - subordinate reports are collated and fed up the chain of command, so the upper echelons write their reports with all the information in hand) give the correct (earlier) timings. Burnside gives times two hours or so later than everyone else involved, and he does so as a conscious change.

To my knowledge Burnside claims he received the order to attack around 10, while most of those subordinate reports put the number at 9. I think this is a case of Burnside genuinely misremembering when he was given the order. Making up a fabrication to cover his own tracks does not fit with his conduct before or after Antietam.

 

[Saphroneth]

To my knowledge Burnside claims he received the order to attack around 10, while most of those subordinate reports put the number at 9. I think this is a case of Burnside genuinely misremembering when he was given the order. Making up a fabrication to cover his own tracks does not fit with his conduct before or after Antietam.

But Burnside has those reports. He can see based on that that everyone else is giving a 9AM time.
We also have at least one actual order, the 9:10 order, and as noted it seems to be a copy of an earlier 8AM order which hasn't survived.


Basically Burnside is going against everyone else by at least two hours, and this significantly telescopes the time his force spent failing to take the bridge. This is of course not in and of itself evidence that he deliberately lied, but you have to consider probabilities here - the options are that Burnside deliberately lied (in that he moved the initial order ca. two hours later) or that he was honestly mistaken (and instead believed that every single one of his subordinates was jointly incorrect about the time despite in many cases giving independent reports).

If the latter is the case, Burnside still is rejecting information which paints him in a negative light and ignoring the reports of all his subordinates to do so. Whether this is a deliberate or accidental lie is functionally something we could only know by actually knowing his mental state on that day, but the practical effect is the same.

 

[Old Burn]

But Burnside has those reports. He can see based on that that everyone else is giving a 9AM time.
We also have at least one actual order, the 9:10 order, and as noted it seems to be a copy of an earlier 8AM order which hasn't survived.


Basically Burnside is going against everyone else by at least two hours, and this significantly telescopes the time his force spent failing to take the bridge. This is of course not in and of itself evidence that he deliberately lied, but you have to consider probabilities here - the options are that Burnside deliberately lied (in that he moved the initial order ca. two hours later) or that he was honestly mistaken (and instead believed that every single one of his subordinates was jointly incorrect about the time despite in many cases giving independent reports).

If the latter is the case, Burnside still is rejecting information which paints him in a negative light and ignoring the reports of all his subordinates to do so. Whether this is a deliberate or accidental lie is functionally something we could only know by actually knowing his mental state on that day, but the practical effect is the same.

Are there really that many reports from Burnsides brigades that make a reference to 9 AM? As far as I can tell, the only reports on the Union side that mention that time are Cox, Ferrero, and Joseph Gerhardt. Gerhardt doesn't say that his unit was ordered to attack at 9 AM, it says that they left camp at that time and made their way to the creek. Ferrero also doesn't say that he received a 9 AM attack order. He was ordered to advance his forces to near the bridge, but he wouldn't attack for a few hours. The only report I've seen that specifically mentions an order to attack coming at 9 AM was Cox, who as we know would later change his mind on this matter. Maybe I'm misinterpreting the Ferrero/Gerhardt orders, but at least to me it seems that the only report that makes a clear reference to a 9 AM attack order was Cox, and it seems reasonable enough to me for Burnside to have genuinely believed that Cox was incorrect.

 

[Old Burn]

Whether this is a deliberate or accidental lie is functionally something we could only know by actually knowing his mental state on that day, but the practical effect is the same.

While its true that we can't know Burnsides mental state at Antietam, that's not really the point I'm trying to make. I'm just saying that it would be very out of character for Burnside to lie about this, give his propensity to often take on a larger share of the blame than he deserved, such as he did at Fredericksburg.

 

[Saphroneth]

Are there really that many reports from Burnsides brigades that make a reference to 9 AM? As far as I can tell, the only reports on the Union side that mention that time are Cox, Ferrero, and Joseph Gerhardt. Gerhardt doesn't say that his unit was ordered to attack at 9 AM, it says that they left camp at that time and made their way to the creek. Ferrero also doesn't say that he received a 9 AM attack order. He was ordered to advance his forces to near the bridge, but he wouldn't attack for a few hours. The only report I've seen that specifically mentions an order to attack coming at 9 AM was Cox, who as we know would later change his mind on this matter. Maybe I'm misinterpreting the Ferrero/Gerhardt orders, but at least to me it seems that the only report that makes a clear reference to a 9 AM attack order was Cox, and it seems reasonable enough to me for Burnside to have genuinely believed that Cox was incorrect.

That's assuming that Burnside not only doesn't remember the time but that he doesn't remember the whole sequence of events. Remember, the true sequence of events is that all of those things happened shortly after Burnside issues orders in response to the first attack order he got (or possibly the second, the 9:10 one).

According to his claim about the 10AM order being the first one he got, all these events which are described as happening (which we know happened in the same time frame as the order to attack the bridge) would instead have happened an hour or more before the sequence of orders which Burnside issued in response to the attack order.

While its true that we can't know Burnsides mental state at Antietam, that's not really the point I'm trying to make. I'm just saying that it would be very out of character for Burnside to lie about this, give his propensity to often take on a larger share of the blame than he deserved, such as he did at Fredericksburg.

Though characters change; perhaps it's unlikely for Burnside to minimize his own blame for an event, but then the other unlikely thing is that Burnside has a fundamentally incorrect picture of what happened when on the 17th, by a margin of several hours.

Given Burnside's claims about his orders to Frankin at Fredericksburg which also have the effect of shifting the blame off himself, I don't think it's so "very out of character" as you claim, either - Burnside issued orders which did not envisage a full-court attack by Franklin, then claimed he had.

 

[Old Burn]

That's assuming that Burnside not only doesn't remember the time but that he doesn't remember the whole sequence of events. Remember, the true sequence of events is that all of those things happened shortly after Burnside issues orders in response to the first attack order he got (or possibly the second, the 9:10 one).

According to his claim about the 10AM order being the first one he got, all these events which are described as happening (which we know happened in the same time frame as the order to attack the bridge) would instead have happened an hour or more before the sequence of orders which Burnside issued in response to the attack order.

I'm a little confused as to what you're saying here, can you try to clarify?

 

[Saphroneth]

I'm a little confused as to what you're saying here, can you try to clarify?

So basically, Burnside has a series of experiences on the 17th which include his getting instructions from McClellan and then issuing orders.

The actual series of events (as in, which order they happened) includes Burnside getting an attack order at 8, and then another just after 9. It also includes Burnside issuing orders for the movements of various parts of his corps, and those units moved around 9AM.


In Burnside's series of events, if he genuinely believed he did not get an attack order until hours later (ie. 10AM or later) then all those events have to be shifted later. Because he knows when he issued the movement orders relative to when he got the attack order, in terms of "it happened before" or "it happened after".

So if Burnside believes he didn't get an attack order until 10AM or later, but he can see that the reports all show elements of his corps moving around 9AM, he has to believe that he issued the movement orders before getting an attack order - not after.


Which is inverting the order of events, a much more difficult thing to mis-remember than just the time.

 

[Old Burn]

That's assuming that Burnside not only doesn't remember the time but that he doesn't remember the whole sequence of events. Remember, the true sequence of events is that all of those things happened shortly after Burnside issues orders in response to the first attack order he got (or possibly the second, the 9:10 one).

According to his claim about the 10AM order being the first one he got, all these events which are described as happening (which we know happened in the same time frame as the order to attack the bridge) would instead have happened an hour or more before the sequence of orders which Burnside issued in response to the attack order.


Though characters change; perhaps it's unlikely for Burnside to minimize his own blame for an event, but then the other unlikely thing is that Burnside has a fundamentally incorrect picture of what happened when on the 17th, by a margin of several hours.

Given Burnside's claims about his orders to Frankin at Fredericksburg which also have the effect of shifting the blame off himself, I don't think it's so "very out of character" as you claim, either - Burnside issued orders which did not envisage a full-court attack by Franklin, then claimed he had.

Well, it was after the battle of Fredericksburg where Burnside issued a state accepting full blame for the defeat, despite the fact that most people at the time were blaming the administration. I would also disagree with your characterization of his orders to Franklin. Although they weren't exactly models of technical clarity, they evidence indicates that Burnside did want Franklin to make a full attack. Certainly, he didn't want him to make a reconnaissance in force with half of the army.

 

[Old Burn]

So basically, Burnside has a series of experiences on the 17th which include his getting instructions from McClellan and then issuing orders.

The actual series of events (as in, which order they happened) includes Burnside getting an attack order at 8, and then another just after 9. It also includes Burnside issuing orders for the movements of various parts of his corps, and those units moved around 9AM.


In Burnside's series of events, if he genuinely believed he did not get an attack order until hours later (ie. 10AM or later) then all those events have to be shifted later. Because he knows when he issued the movement orders relative to when he got the attack order, in terms of "it happened before" or "it happened after".

So if Burnside believes he didn't get an attack order until 10AM or later, but he can see that the reports all show elements of his corps moving around 9AM, he has to believe that he issued the movement orders before getting an attack order - not after.


Which is inverting the order of events, a much more difficult thing to mis-remember than just the time.

Do we know exactly what orderes Ferrero and Gerhardt were following? Burnside also got the 7 AM order to get his troops into position to attack, perhaps Gerhardt and Ferrero's subsequent movements were associated with that. In the case of those two, the 9 AM orders they received doesn't seem to be an attack order, but just an order to move up.

 

[EHParks]

The following is from something I'm working on regarding Burnside at Antietam. I'd greatly appreciate any insights or other input other members may have on the subject.

It is a commonly known fact that Burnside and McClellan were at odds since the Battle of South Mountain. Even as recently as the morning of the 17th, McClellan had officially chastised his long-time friend for his repeated failure to comply with various orders. On the 15th, their relationship was further strained when McClellan issued the following directive, "The operation of the Special Orders of yesterday's date, assigning General Burnside to the command of the right wing, owing to the necessary separation of the Third [First] Corps, is temporarily suspended. General Hooker will report direct to these headquarters."

The Ninth Corps had only just officially been formed on July 22nd, with Burnside at its head. Throughout the course of the next couple of months, the new Corps commander would be tasked with a series of temporary assignments, including that of commander of the right wing at the outset of the Antietam Campaign. Consequently, it became necessary to appoint Jesse Reno and then, following the latter's death, Jacob Cox to the temporary command of the Ninth. It stands to reason that upon receipt of McClellan's order suspending the wing, Burnside's responsibilities should have automatically reverted to that of commander of the Ninth Corps.

As it was, Burnside had shown little initiative over recent days but he would show even less on the morning of the 17th. Apparently convinced that taking personal charge of his Ninth Corps would be tantamount to accepting a perceived slight from McClellan, Burnside insisted that Cox remain in temporary command. In a petulant display, he resorted to following McClellan's orders to the letter, doing no more or arbitrarily forwarding them on to Cox. Already uncomfortable in his interim role and having no latitude, Cox could do little but execute the various orders reaching him from Burnside, or from McClellan via Burnside.

"It was an awkward diffusion of command responsibility, made all the worse by McClellan's failure to smooth his old friend's ruffled feathers or to clarify just what was expected of him in the coming fight," writes Stephen W. Sears. At such an exceedingly critical juncture in the Maryland Campaign, it's certain that McClellan would have had more important things to do than spend his time smoothing Burnside's or any one else's ruffled feathers. These were not children that McClellan was dealing with. They were responsible military men who were about to enter into one of the greatest battles of the entire war, on whose result the fate of the nation hinged.

It must also be wondered what it was that needed clarifying. As already mentioned above, upon the suspension of the right wing, Burnside's function should have automatically reverted to that of commander of the Ninth Corp. This should have gone without saying (Cox even urged him to do so.) As such McClellan would have expected his "old friend" to perform his duties as corps commander to the best of his abilities and to follow any and all orders as were sent to him. What else was there to clarify? If Burnside had any concerns regarding his role, following the temporary suspension of the wing, he should have communicated these to McClellan. He did not.

It's difficult to imagine how McClellan can, in any way, be blamed for the "awkward diffusion of command responsibility" that existed on the 17th. Burnside had created it and Burnside alone was responsible.

I can only add that no overall commander of troops is ever absolved of final responsibility for them, even if adverse actions were taken by subordinates. Even if the natural assumption would be that Burnside would devolve to his old command after the change of a temporary order - that should never have been taken as a given and McClellan or his staff needed to make sure who was in command for real and that orders were being carried out efficiently.

 

[67th Tigers]

To my knowledge Burnside claims he received the order to attack around 10, while most of those subordinate reports put the number at 9. I think this is a case of Burnside genuinely misremembering when he was given the order. Making up a fabrication to cover his own tracks does not fit with his conduct before or after Antietam.

The 11th Connecticut attacked at 0900 by all accounts, in response to orders from Burnside which were in response to orders from McClellan. The divisions in the rear all likewise received orders at 0900.

Thus it is clear that Burnside was responding to attack orders received before 0900.

How Burnside came to alter the timings is an interesting question, but it is clear that he did, whilst extracting Cox's report which gives 0900 as the first attack time.

Do we know exactly what orderes Ferrero and Gerhardt were following? Burnside also got the 7 AM order to get his troops into position to attack, perhaps Gerhardt and Ferrero's subsequent movements were associated with that. In the case of those two, the 9 AM orders they received doesn't seem to be an attack order, but just an order to move up.

The only source on the pre-0700 order is Cox, who reported that on returning from getting Rodman moving, he was told Burnside had received an order from McClellan. The time is unknown, since Cox departed before 0600 to move Rodman.

Again, Burnside did attack at 0900. Ergo he must have received the attack order before this.

 

[67th Tigers]

It is worth noting that Rafuse wrote an article on the Burnside-McClellan relationship at Antietam. To quote some:

For his part, Carman speculated that, "As McClellan was also involved in the charges of disloyalty to Pope and the administration it was easy for him to sympathize with Porter and share his feelings toward Burnside, so, putting aside all remembrances of what Burnside had done for him ... [McClellan] joined hands with Porter, and from that hour became Burnside's enemy." (28)
But, it must be asked, does it really require a conspiracy theory to explain McClellan's actions toward Burnside on September 15? Indeed, if anything, it is remarkable how gentle McClellan was with his old friend that day. The delay in getting a force marching from Fox's Gap into Pleasant Valley meant that a critical component of McClellan's plan for September 15 had been ruined. Moreover, McClellan knew from Hooker's regular reports that Richardson and the First Corps had spent the morning pursuing the rear guard of Lee's army through Boonsboro and along the road from Boonsboro to Sharpsburg. (29) According to McClellan's plan, at noon the Ninth Corps was supposed to be either pressing Lee's army from the east as it retreated or supporting Franklin's effort to save Harpers Ferry. Instead, Burnside was doing neither. While it is debatable, given the feebleness with which its defense was conducted, whether Harpers Ferry could have been saved, the presence of another corps in Pleasant Valley might have encouraged Franklin to be more aggressive than he was in dealing with the Confederate forces he encountered after pushing through Crampton's Gap. Alternately, an aggressive march by the Ninth Corps west along the Old Sharpsburg Road, as McClellan directed Burnside, "keep[ing] the head of your column as near parallel as possible to that of Richardson," would have severely complicated Lee's flight behind the Antietam and would have meant that McClellan had more than two divisions on hand when he contemplated whether to attack Lee's position during the afternoon of September 15. (30) Indeed, had Burnside reached the Keedysville-Porterstown area earlier, he might have linked back up with Hooker's corps and eliminated what would be the principal rationale for sending the First and Ninth corps into battle at opposite ends of the field at Antietam.
After reaching Boonsboro, McClellan remained there a few hours coordinating operations in Pleasant Valley with the forces on the opposite side of Elk Ridge that were pressing the Confederates along the road from Boonsboro to the Potomac crossing at Shepherdstown. Shortly before noon, McClellan learned Hooker had found the rebels had halted their retreat and taken up a defensive position behind Antietam Creek. Then, during the afternoon, McClellan left Boonsboro in response to a message from Sumner, who as senior officer on the field had just assumed direction of affairs west of Elk Ridge from Hooker, that requested permission to make preparations to attack the rebel position. McClellan arrived at Keedysville shortly before three in the afternoon and met with Hooker and Sumner, from whom he learned Lee had thirty thousand to fifty thousand men in a strong position behind the Antietam. Hooker also advised McClellan that a staff officer had identified a number of good crossings of the creek upstream from the Middle Bridge that carried the Boonsboro Pike over the Antietam. Shortly thereafter, Porter arrived with Sykes's division and joined the discussion. (31)
When McClellan personally arrived on the scene, he found his men posted in good positions on the east side of the Antietam. The first significant body of Union troops to reach Keedysville, Richardson's division, had deployed astride the Boonsboro Pike with skirmishers advanced to the Antietam by early in the afternoon. When Sykes's division arrived from Fox's Gap, it deployed to Richardson's left behind the bluffs overlooking the Antietam south of the Boonsboro Pike. Following behind Sykes was the Ninth Corps, which had been diverted temporarily during its march to the Antietam by orders to stop at Rohrersville to support Franklin in Pleasant Valley. When it had become clear that there was nothing in Pleasant Valley that Franklin needed help handling, Burnside pushed on to join the rest of the Army of the Potomac via Springvale. (32)
Leading the Ninth Corps as it marched to join the rest of the army were Burnside and Cox. If there were any hard feelings from the problems at Fox's Gap earlier in the day or a scheme afoot to destroy Burnside, they were not evident on the afternoon of the fifteenth. Upon their arrival on the field, Cox later recalled he and Burnside were "very cordially greeted by General McClellan. He and Burnside were evidently on terms of most intimate friendship and familiarity. He introduced me to the officers I had not known ... putting me upon an easy footing with them in a very agreeable and genial way." McClellan then led his subordinates up a high ridge to reconnoiter the enemy position. Shortly after McClellan and his men reached the top, though, Confederate artillerists began firing at their position. McClellan then dismissed all but Porter from the hill, and together they continued their inspection of the ground on the other side of the Antietam. By the time McClellan was finished, he had decided it was too late in the day to attempt an attack on the strong Confederate position. He was also determined to try using the crossings Hooker's staff officer had located to try to get at the rebel left. Since Hooker's men knew where the crossings were and Hooker's corps was then approaching the field from Boonsboro--and thus would be conveniently located to make such a movement--it was natural that McClellan would assign this task to the First Corps. (33)
McClellan's plan for the Battle of Antietam called for Hooker to cross the Antietam above the Middle Bridge and attack the Confederate left north of Sharpsburg. McClellan would monitor Hooker's progress and base the timing of an attack by Burnside's command against the Confederate right on events north of the town. Recognizing that the terrain would make a successful attack across the creek more difficult in Burnside's sector, McClellan no doubt hoped Hooker's attack would induce Lee to shift forces north to counter it, which would make it easier for Burnside to get across the Antietam and, once across, advance to a position that might cut Lee off from his only line of retreat across the Potomac. Once one or both of these attacks achieved success (or events proved Lee had the strength to handle both of them), McClellan would deliver a stroke against the Confederate center, which was sure to be weakened if Lee hoped to counter both Hooker and Burnside. To make this attack, McClellan evidently intended to have at least two corps in the center, with their commitment to the battle contingent on events. (34) The plan delegated a great deal of authority to both Hooker and Burnside, something further necessitated by the fact that McClellan would have to maintain a central position during the battle to manage the commitment of forces to the engagement after Hooker began his attack.

 

[Old Burn]

It is worth noting that Rafuse wrote an article on the Burnside-McClellan relationship at Antietam. To quote some:

For his part, Carman speculated that, "As McClellan was also involved in the charges of disloyalty to Pope and the administration it was easy for him to sympathize with Porter and share his feelings toward Burnside, so, putting aside all remembrances of what Burnside had done for him ... [McClellan] joined hands with Porter, and from that hour became Burnside's enemy." (28)
But, it must be asked, does it really require a conspiracy theory to explain McClellan's actions toward Burnside on September 15? Indeed, if anything, it is remarkable how gentle McClellan was with his old friend that day. The delay in getting a force marching from Fox's Gap into Pleasant Valley meant that a critical component of McClellan's plan for September 15 had been ruined. Moreover, McClellan knew from Hooker's regular reports that Richardson and the First Corps had spent the morning pursuing the rear guard of Lee's army through Boonsboro and along the road from Boonsboro to Sharpsburg. (29) According to McClellan's plan, at noon the Ninth Corps was supposed to be either pressing Lee's army from the east as it retreated or supporting Franklin's effort to save Harpers Ferry. Instead, Burnside was doing neither. While it is debatable, given the feebleness with which its defense was conducted, whether Harpers Ferry could have been saved, the presence of another corps in Pleasant Valley might have encouraged Franklin to be more aggressive than he was in dealing with the Confederate forces he encountered after pushing through Crampton's Gap. Alternately, an aggressive march by the Ninth Corps west along the Old Sharpsburg Road, as McClellan directed Burnside, "keep[ing] the head of your column as near parallel as possible to that of Richardson," would have severely complicated Lee's flight behind the Antietam and would have meant that McClellan had more than two divisions on hand when he contemplated whether to attack Lee's position during the afternoon of September 15. (30) Indeed, had Burnside reached the Keedysville-Porterstown area earlier, he might have linked back up with Hooker's corps and eliminated what would be the principal rationale for sending the First and Ninth corps into battle at opposite ends of the field at Antietam.
After reaching Boonsboro, McClellan remained there a few hours coordinating operations in Pleasant Valley with the forces on the opposite side of Elk Ridge that were pressing the Confederates along the road from Boonsboro to the Potomac crossing at Shepherdstown. Shortly before noon, McClellan learned Hooker had found the rebels had halted their retreat and taken up a defensive position behind Antietam Creek. Then, during the afternoon, McClellan left Boonsboro in response to a message from Sumner, who as senior officer on the field had just assumed direction of affairs west of Elk Ridge from Hooker, that requested permission to make preparations to attack the rebel position. McClellan arrived at Keedysville shortly before three in the afternoon and met with Hooker and Sumner, from whom he learned Lee had thirty thousand to fifty thousand men in a strong position behind the Antietam. Hooker also advised McClellan that a staff officer had identified a number of good crossings of the creek upstream from the Middle Bridge that carried the Boonsboro Pike over the Antietam. Shortly thereafter, Porter arrived with Sykes's division and joined the discussion. (31)
When McClellan personally arrived on the scene, he found his men posted in good positions on the east side of the Antietam. The first significant body of Union troops to reach Keedysville, Richardson's division, had deployed astride the Boonsboro Pike with skirmishers advanced to the Antietam by early in the afternoon. When Sykes's division arrived from Fox's Gap, it deployed to Richardson's left behind the bluffs overlooking the Antietam south of the Boonsboro Pike. Following behind Sykes was the Ninth Corps, which had been diverted temporarily during its march to the Antietam by orders to stop at Rohrersville to support Franklin in Pleasant Valley. When it had become clear that there was nothing in Pleasant Valley that Franklin needed help handling, Burnside pushed on to join the rest of the Army of the Potomac via Springvale. (32)
Leading the Ninth Corps as it marched to join the rest of the army were Burnside and Cox. If there were any hard feelings from the problems at Fox's Gap earlier in the day or a scheme afoot to destroy Burnside, they were not evident on the afternoon of the fifteenth. Upon their arrival on the field, Cox later recalled he and Burnside were "very cordially greeted by General McClellan. He and Burnside were evidently on terms of most intimate friendship and familiarity. He introduced me to the officers I had not known ... putting me upon an easy footing with them in a very agreeable and genial way." McClellan then led his subordinates up a high ridge to reconnoiter the enemy position. Shortly after McClellan and his men reached the top, though, Confederate artillerists began firing at their position. McClellan then dismissed all but Porter from the hill, and together they continued their inspection of the ground on the other side of the Antietam. By the time McClellan was finished, he had decided it was too late in the day to attempt an attack on the strong Confederate position. He was also determined to try using the crossings Hooker's staff officer had located to try to get at the rebel left. Since Hooker's men knew where the crossings were and Hooker's corps was then approaching the field from Boonsboro--and thus would be conveniently located to make such a movement--it was natural that McClellan would assign this task to the First Corps. (33)
McClellan's plan for the Battle of Antietam called for Hooker to cross the Antietam above the Middle Bridge and attack the Confederate left north of Sharpsburg. McClellan would monitor Hooker's progress and base the timing of an attack by Burnside's command against the Confederate right on events north of the town. Recognizing that the terrain would make a successful attack across the creek more difficult in Burnside's sector, McClellan no doubt hoped Hooker's attack would induce Lee to shift forces north to counter it, which would make it easier for Burnside to get across the Antietam and, once across, advance to a position that might cut Lee off from his only line of retreat across the Potomac. Once one or both of these attacks achieved success (or events proved Lee had the strength to handle both of them), McClellan would deliver a stroke against the Confederate center, which was sure to be weakened if Lee hoped to counter both Hooker and Burnside. To make this attack, McClellan evidently intended to have at least two corps in the center, with their commitment to the battle contingent on events. (34) The plan delegated a great deal of authority to both Hooker and Burnside, something further necessitated by the fact that McClellan would have to maintain a central position during the battle to manage the commitment of forces to the engagement after Hooker began his attack.

Is there any actual evidence other than Carman's speculation that Burnside considered Mclellan an enemy during Antietam? And it was hardly Burnsides fault that the IX corps wasn't able to move out quickly from Fox's gap. Not only were his troops exhausted from the previous days fighting, but according to Cox no order to advance was received until noon on the 15th.