Hancock's men marched almost all night and arrived too worn-out for an immediate attack that morning. Grant agreed to let the men rest and postponed the attack until 5 p.m., and then again until 4:30 a.m. on June 3. But Grant and Meade did not give specific orders for the attack, leaving it up to the corps commanders to decide where they would hit the Confederate lines and how they would coordinate with each other. No senior commander had reconnoitered the enemy position. Robert E. Lee took advantage of the Union delays to bolster his defenses. When Hancock departed Totopotomoy Creek, Lee was free to shift Breckinridge's division to his far right flank. He also moved troops from A. P. Hill's Third Corps, the divisions of Brig. Gens. William Mahone and Cadmus M. Wilcox, to support Breckinridge, and stationed cavalry under Fitzhugh Lee to guard the army's right flank. The result was a curving line on low ridges, long, with the left flank anchored on Totopotomoy Creek, the right on the Chickahominy River, making any flanking moves impossible. Lee's engineers used their time effectively and constructed the "most ingenious defensive configuration the war had yet witnessed."