Corps were selected for the assault, commanded by Brig. Gens. Joseph Hooker and Philip Kearny. Facing them was the division of Confederate Maj. Gen. Benjamin Huger. Opposing forces Union Confederate Battle At 8:30 a.m., June 25, three Union brigades stepped off in orderly line of battle. From right to left, they were commanded by Brig. Gen. Daniel E. Sickles (the Excelsior Brigade), Brig. Gen. Cuvier Grover, both of Hooker's division, and Brig. Gen. John C. Robinson from Kearny's division. Although Robinson and Grover made good progress on the left and in the center, Sickles's New Yorkers encountered difficulties moving through their abatis, then through the upper portions of the swamp, and finally met stiff Confederate resistance, all of which threw the Federal line out of alignment. Huger took advantage of the confusion by launching a counterattack with the brigade of Brig. Gen. Ambrose R. Wright against Grover's brigade. Adding to the confusion, one of Wright's Georgia regiments wore red Zouave uniforms. Many of Grover's men believed that only the Union Army had Zouave units, so were reluctant to fire on their own men. When they finally realized that Union troops would not be approaching from the direction of Richmond, they opened fire. At a crucial moment in the battle, the 26th North Carolina of Brig. Gen. Robert Ransom's brigade, in their first combat engagement, delivered a perfectly synchronized volley of rifle fire against Sickles's brigade, breaking up its delayed attack and sending the 71st New York into a panicked retreat, which Sickles described as "disgraceful confusion." Informed of Sickles's reverse, corps commander Heintzelman ordered reinforcements sent forward and also notified army commander McClellan, who was attempting to manage the battle by telegraph from away. McClellan, unaware of most details of the engagement, became alarmed and at 10:30 a.m. ordered his men to withdraw back to their entrenchments, an order that mystified his subordinates on the scene. He telegraphed that he would be arriving at the front in person, which caused a 2.5 hour lull in the action. At 1 p.m., seeing that the situation was not as bad as he had feared, McClellan ordered his men forward to retake the ground for which they had already fought once that day. The fighting lasted until nightfall. Aftermath The minor battle was McClellan's only tactical offensive action against Richmond. His attack gained only at a cost of over 1,000 casualties on both