On February 25, 1863, Confederate cavalry under Brig. Gen. Fitzhugh Lee, one of Stuart's key subordinates and a nephew of Gen. Robert E. Lee, led a force of 400 troopers in a raid near Hartwood Church in Stafford County, 9 miles northwest of Fredericksburg. The federal cavalry was ineffective in pursuing Lee and managed to lose 150 prisoners from the division of Brig. Gen. William W. Averell, one of Fitz Lee's closest friends at West Point. Hooker was furious and threatened to relieve Stoneman of his command if he did not stop Confederate raids of this type.