 He launched a powerful assault at 6 a.m. that overran the Confederate skirmishers but mistakenly thought he had pierced the first line of earthworks and halted his corps to regroup before moving on, which he planned for that afternoon.At 7 a.m. Grant advised Meade to vigorously exploit any successful part of the assault.Meade ordered his three corps commanders on the left to assault at once, without regard to the movements of their neighboring corps.