In April 1862, Union forces under General George B. McClellan began a major campaign to capture Richmond, marching east from Fort Monroe up the Peninsula between the York and James Rivers toward the Confederate capital, while Confederate General Joseph E. Johnston's smaller army opposed them. Slowly but inevitably, the Federal advance overcame three Southern defensive lines and reached Richmond's eastern suburbs, but new commander Robert E. Lee led a Confederate offensive during the Seven Days' Battles at the end of June that drove the Union army away. After the twilight battle at Savage's Station on June 29, 1862, the Union Army of the Potomac abandoned the remnants of its line in front of Richmond and retreated south through the darkness toward the James River. Once across White Oak Swamp, it deployed to challenge the Confederate pursuit, with General William F. Smith's and General Israel Richardson's divisions occupying the heights there. Confederate General Thomas J. "Stonewall" Jackson's 25,000 men arrived on the north bank of the swamp at noon on June 30 and found the bridge destroyed. Although the sound of heavy fighting three miles southwest at Glendale made Jackson eager to press forward, he did not advance and instead settled for an artillery duel. Vague orders, the burned bridge, and the strong Federal position held Jackson back for the remaining eight hours of daylight. This failure to advance deprived Lee of his offensive punch, allowed a successful Union defense of the roads to the James River, and opened Jackson to criticism.
