Following the Union embarrassment at the First Battle of Bull Run, General George B. McClellan replaced Irvin McDowell. The new commander’s plan involved building up a massive army over the winter of 1861-62, then capturing the Confederate capital of Richmond by pushing up the peninsula between the York and James rivers. President Lincoln was not enthusiastic about the plan, fearing that Washington would be exposed to attack. Before this campaign was undertaken, both sides awaited the conclusion of a naval engagement-the Battle of Hampton Roads-in which the famed Monitor and Merrimack fought to a draw. In April 1862 McClellan landed a force of more than 100,000 men at Fort Monroe, catching the Confederate leaders by surprise; they had been expecting an overland attack against Richmond. McClellan’s Army of the Potomac set up siege operations outside of Yorktown. As the attack was about to commence, the defending forces under Joseph E. Johnston retreated up the peninsula. Johnston did a masterly job of confusing his opponents; by rapidly deploying his soldiers he conveyed the impression of possessing a much larger force. In late May, Johnston was seriously wounded at the Battle of Seven Pines (or the Battle of Fair Oaks) south of Richmond and was replaced by Robert E. Lee. Lee performed admirably from the beginning. He successfully thwarted the reinforcement of McClellan’s force by sending Stonewall Jackson on a feint toward Washington. McDowell stayed near the capital rather than joining McClellan. Jackson stopped at the Potomac and headed south to supplement Lee’s army. Lee’s position was greatly enhanced by the daring reconnaissance exploits of J.E.B. Stuart, the famed cavalry leader. An extended engagement followed in the Richmond area, called the Seven Days’ Battles: