The Battle of Gaines' Mill, Virginia was fought on this day in 1862. This battle was part of the Seven Days' Battles (Peninsula Campaign) of the American Civil War. Following the inconclusive Battle of Beaver Dam Creek, Confederate General Robert E. Lee renewed his attacks against the right flank of the Federal Army, relatively isolated on the northern side of the Chickahominy River. Federal Brigadier General Fitz John Porter's V Corps had established a strong defensive line behind Boatswain's Swamp. Lee's army was destined to launch the largest Confederate attack of the war, about 57,000 men in six divisions. Porter's reinforced V Corps held fast for the afternoon as the Confederates attacked in a disjointed manner, first with the division of Major General A.P. Hill, then Major General Richard S. Ewell, suffering heavy casualties. The arrival of Major General Thomas "Stonewall" Jackson's command was delayed, preventing the full concentration of Confederate force before Porter received some reinforcements from the VI Corps. At dusk, the Confederates finally mounted a coordinated assault that broke Porter's line and drove his men back toward the Chickahominy River. The Federals retreated across the river during the night. The Confederates were too disorganized to pursue the main Federal force. The Battle of Gaines' Mill saved Richmond for the Confederacy in 1862.