the Pamunkey River, which ran roughly parallel to the Chickahominy, offered a line of communication that could enable McClellan to get around Johnston's left flank. Second, McClellan anticipated the arrival of the I Corps under Maj. Gen. Irwin McDowell, scheduled to march south from Fredericksburg to reinforce his army, and thus needed to protect their avenue of approach. The Army of the Potomac pushed slowly up the Pamunkey, establishing supply bases at Eltham's Landing, Cumberland Landing, and White House Landing. White House, the plantation of W.H.F. "Rooney" Lee, son of General Robert E. Lee, became McClellan's base of operations. Using the Richmond and York River Railroad, McClellan could bring his heavy siege artillery to the outskirts of Richmond. He moved slowly and deliberately, reacting to faulty intelligence that led him to believe the Confederates outnumbered him significantly. By the end of May, the army had built a few bridges across the Chickahominy and was facing Richmond, straddling the river, with one third of the Army south of the river, two thirds north. Opposing forces Union The Union Army of the Potomac of 105,000 men was near the outskirts of Richmond to the northeast, straddling the Chickahominy River. There were three corps north of the river, protecting the Union railroad supply line: the V Corps under Brig. Gen. Fitz John Porter; the VI Corps, under Brig. Gen. William B. Franklin; and the II Corps, under Brig. Gen. Edwin V. Sumner. South of the river were the IV Corps, under Brig. Gen. Erasmus D. Keyes, in a position far forward and close to the Confederate lines; and the III Corps, under Brig. Gen. Samuel P. Heintzelman. At the start of the battle on May 31, McClellan was confined to bed, ill with a flare-up of his chronic malaria. Confederate Johnston had 60,000 men in his Army of Northern Virginia protecting the defensive works of Richmond in eight divisions commanded by Maj. Gen James Longstreet, Maj. Gen D.H. Hill, Maj. Gen Benjamin Huger, Maj. Gen Gustavus Smith, Maj. Gen A.P. Hill (who had just gotten command of a brand-new division on May 27), Maj. Gen John B. Magruder, Brig. Gen David Rumph Jones, and Maj. Gen Lafayette McLaws. Just prior to the battle, Johnston appointed Longstreet, Smith, and Magruder as wing commanders. Longstreet had the right wing, consisting of his own division, D.H. Hill's, and Huger's. Smith had the left wing, consisting of