He then succeeded to the command of a division of cavalry, and continued in that position till the close of his service, at times temporarily commanding the Cavalry Corps.

He was the only division commander I had whose experience had been almost exclusively derived from the cavalry arm.
Wilson graduated in 1860 in the Topographical Engineers, and was first assigned to duty in Oregon, where he remained till July, 1861.
In the fall of that year his active service in the war began, and he rose from one position to another, in the East and West, till, while on General Grant's staff, he was made a brigadier-general in the fall of 1863 in reward for services performed during the Vicksburg campaign and for engineer duty at Chattanooga preceding the battle of Missionary Ridge.

At my request he was selected to command the Third Division.

General Grant thought highly of him, and, expecting much from his active mental and physical ability, readily assented to assign him in place of General Kilpatrick.

The only other general officers in the corps were Brigadier-General Wesley Merritt, Brigadier-General George A.Custer, and Brigadier-General Henry E.
Davies, each commanding a brigade.
In a few days after my arrival at Brandy Station I reviewed my new command, which consisted of about twelve thousand officers and men, with the same number of horses in passable trim.