That's often assumed to be the case. Can you cite specific language in the Regulations (or maybe Customs of Service) which actually requires it? I know in some cases regiments were thrown together using the next ten companies available from a Camp of Instruction, and it seems hard to believe that this rule was invariably followed "to the letter"
.
Let's see.
1821 Regulations;
“A the first organization of a regiment or independent battalion, the companies will be designated by letters of the alphabet, giving the first letters to the flank companies [A & B],
according to the rank of the respective captains, or,
if the rank be not settled, by lottery—and the next highest letters of the alphabet [
C thru K]
to the remaining companies, on the same principle. Designations so given will be as permanent as the regiment or independent battalion.
A change in the relative rank of captains will of course change the positions of the companies in the habitual order of battle, whether the captains be present or not, but will not change the letters of the companies.” [Art. XXIV, para. 1-2.]
The 1825 regulations stated the same. [1825 Regulations, para. 152.]:
“At the first organization of a regiment or battalion, the companies will be designated by letters of the alphabet, giving the first letters to the flank companies, according to the rank of the respective captains;
or, if the rank be not settled, by lottery. And the next highest letters of the alphabet, to the remaining companies, on the same principle.
Designations so given, will be as permanent as the regiment or battalion.
A change in the relative rank of the captains, will, of course, change the positions of the companies in the habitual order of battle, whether the captains be present or not; but will not change the letters of the companies.” [1825; Art. XXIV, para. 152.]
General Alexander Macomb’s proposed regulations (printed 1834) are similar:
“On the organization of a regiment or battalion, the companies will be designated by the letters of the alphabet, which designation is to be permanent. The captains, in the first instance, are to be assigned to companies according to seniority, commencing with letter A; after which, those who succeed to the command of companies are to take them in succession as the vacancies may happen, and although the companies will not change their letters, they will take their places in the battalion according to the rank of their respective captains. The lieutenants are to be posted in like manner, and afterwards to succeed to companies as vacancies occur. [Macomb, Regulations, 1834: Art. 10, para. 13.]
Macomb omitted the specific statement that the companies would take post in the line by captain’s seniority;
present or not. However, as written it does not necessarily contradict that practice. As they used to say, "omittance is no quittance..."
Macomb’s approved army regulations were printed in 1835 and were officially in force from January 1, 1837. They state:
“On the organization of a regiment or battalion, the companies will be designated by the letters of the alphabet, which designation is to be permanent. The Captains, in the first instance [
the organization of the regiment], will be assigned to companies according to seniority, commencing with the letter A; after which, they will succeed to the command of them, as the vacancies may happen,
but the companies will take their places in the battalion according to the rank of their respective captains. The Lieutenants are to be posted in like manner, and afterwards to succeed to companies as vacancies occur.” 1835 Regulations, IX, 8-9.]
The major change was omission of the statement that the companies would not change their letters, but that was an established custom, and evidently considered unnecessary to repeat.
The 1835/37 regulations remained in effect until 1841. The regulations adopted the latter year state the same, but in reference to the places of companies in the battalion notes:
“On the organization of a regiment or battalion, the companies will be designated by the letters of the alphabet, which designation is to be permanent. The Captains, in the first instance, will be assigned to companies according to seniority, commencing with the letter A; after which they will succeed to the command of them, as the vacancies may happen, but the companies will take their places in the battalion according to the rank of their respective Captains. (see system of Infantry Tactics.) the Lieutenants are to be posted in like manner, and afterwards to succeed to companies, as vacancies occur.” [Art. IX, para. 43.]
So in the "infantry tactics", Scott's vol. I, para. 7, he notes the battalion companies "will habitually be posted from right to left, in the following order: first, fifth, fourth, seventh, third, eighth, sixth, second, according to the rank of the captains." The senior captain at organization commanding Co. A, and the second, Co. B, these are flank companies rather than battalion companies, and in this period were intended for light infantry, among the regulars equipped with bugles in lieu of fife and drum, etc. From 1857 with the adoption of Hardee's (and also in Casey's) the distinction of light versus battalion companies was eliminated.
The 1847 Army regulations reference the companies formed by captain’s seniority, and restores the clause, “whether the captains be present or not:"
"On the organization of a regiment or battalion, the companies will be designated by the letters of the alphabet, which designation is to be permanent. The Captains, in the first instance, will be assigned to companies according to seniority, commencing with the letter A; after which they will succeed to the command of them, as the vacancies [
of companies forming the regiment or battalion] may happen, but the companies will take their places in the battalion according to the rank of their respective Captains. (See system of Infantry Tactics.)
A change in the relative rank of the Captains will, of course, change the positions of the companies in the habitual order of battle, whether the Captains be present or not. The Lieutenants are to be posted} in the first instance, in like manner as the Captains, and afterwards to succeed to companies as vacancies occur.” [Art. XIII, para. 105.]
The 1857 Regulations again truncated the paragraph on the subject, again removing specific reference to presence or absence of the captains:
“On the organization of a regiment, the companies receive a permanent designation by letters beginning with A, and the officers are assigned to companies; afterward, company officers succeed to companies, as promoted to fill vacancies.
Companies take place in the battalion according to the rank of their captains.” [Art. XII, para. 69.]
The 1861 US Army regulations state the same. (Art. XII, para. 71), as did the revised regulations of 1863 (Art. XII, 71). The Confederate Army’s regulations of 1862 and 1864 are identical.
The federal regulations of 1863 remained in force long after the war. In 1873 a proposed revision sought to restore the specific reference that companies were to form within a battalion by seniority of captains, whether those captains “be present or not.” These regulations were not adopted, but the inclusion of the reference suggested the custom continued in the Regular US Army from pre-war custom. [“Revised Army Regulations,” March 1, 1873, proposed by Secretary of War Belknap, Art. XXXIII, printed as House Report #85, 42nd Congress, 3rd Session, Reports of Committees of the House of Representatives for the Third Session of the Forty Second Congress, 1872-73, I, Government Printing Office, Washington, DC, 1873, 36; Leiber, G. Norman, Remarks on the Army Regulations, Government Printing Office, Washington, DC, 1898, 57, n.1.]
Consequently the regulations throughout the period discussed intended that the order of companies in line of battle be altered when a permanent change occurred among any but the junior captain of a regiment.
So, from the above review the 1857-1860s regulations are not specific about assigning the letters of companies based on captain's seniority and that explains some units using other methods. Notice using a lottery to assign seniority at organization was omitted from the regulations after 1835, but it seems to have been employed some in the 60s:
When the 96
th Illinois Regiment was formed its senior company was made Company A, and the other captains drew paper lots with letters marked to discern what letter their company would be. They retained the formation by companies (rather than seniority) throughout the regiment’s service. At Chickamauga its Co. C was its color company, as it was at organization. [Partridge,
History of the 96th Regiment; Illinois Volunteer Infantry…32, 733, 735.]
When the 78th Illinois formed in 1861 the companies also cast lots for position in line of battle. Edward M. Robbin’s company came up as Company H, placed on the left of the color-guard, and Company C on the right of it. [Robbins, Edward M., Civil War Experiences, 1862-1865; Chickamauga, Mission Ridge, Buzzard Roost, Resaca, Rome, New Hope Church, Kenesaw Mountain, Peach Tree Creek, Atlanta, Jonesboro, Averysboro, Bentonville, Carthage, IL, 1919.]
The 35th Massachussetts:
By the above, Co. B was their color company, or third company by Hardees tactics.
Meanwhile, the 1st Maryland (CSA) evidently organized with senior captain (Bradley T. Johnson) as Company A.
J. Marshall,
Hernando, FL.