As a part of the division of Maj. Gen. Richard H. Anderson at the Battle of Chancellorsville in May 1863, Wilcox's brigade was instrumental in delaying the Union VI Corps in its drive west from Fredericksburg, Virginia, slowing them at the Battle of Salem Church. Shortly after the battle, Wilcox and his brigade moved with Anderson's division to the newly created Third Corps, under Lt. Gen. A.P. Hill on May 30.