Following Fredericksburg, Burnside was removed from command of the army and replaced by Joe Hooker. Hooker immediately abolished the Grand Divisions and also for the first time organized the cavalry into a proper corps led by George Stoneman instead of having them ineffectually scattered among infantry divisions. Burnside and his old IX Corps departed out to a command in the Western Theater. The I, II, and XII Corps retained the same commanders they had had during the Fredericksburg campaign, but the other corps got new commanders once again. Daniel Butterfield was chosen by Hooker as his new chief of staff and command of the V Corps went to George Meade. Daniel Sickles received command of the III Corps and Oliver Howard the XI Corps after Franz Sigel had resigned, refusing to serve under Hooker, his junior in rank. William Franklin also left the army for the same reason. Edwin Sumner, who was in his 60s and exhausted from campaigning, departed as well and died a few months later. William F. Smith resigned from command of the VI Corps, which was taken over by John Sedgwick. The I and V Corps were not significantly engaged during the Chancellorsville campaign.