American Military History, Volume 1 by Richard W. Stewart

When McClellan reached the peninsula in early April he found a force of ten to fifteen thousand Confederates under Maj. Gen. John B. Magruder barring his path to Richmond. Magruder, a student of drama and master of deception, so dazzled McClellan that instead of brushing the Confederates aside he spent a month in a siege of Yorktown. But Johnston, who wanted to fight the decisive action closer to Richmond, decided to withdraw slowly up the peninsula. At Williamsburg, on May 5, McClellan's advance elements made contact with the Confederate rear guard under Maj. Gen. James Longstreet, who successfully delayed the Federal advance. McClellan again pursued in leisurely fashion, always believing that he was outnumbered and about to be attacked in overwhelming force by Johnston. By May 25 two corps of the Army of the Potomac had turned southwest toward Richmond and crossed the sluggish Chickahominy River. The remaining three corps were on the north side of the stream with the expectation of making contact with McDowell, who would come down from Fredericksburg. Men of the two corps south of the river could see the spires of the Confederate capital, but Johnston's army was in front of them. (See Map 24.)

Drenching rains on May 30 raised the Chickahominy to flood stage and seriously divided McClellan's army. Johnston decided to grasp this chance to defeat the Federals in detail. He struck on May 31 near Fair Oaks. His plans called for his whole force to concentrate against the isolated corps south of the river, but his staff and subordinate commanders were not up to the task of executing them. Assaulting columns became confused, and attacks were delivered piecemeal. The Federals, after some initial reverses, held their ground and bloodily repulsed the Confederates.