Rebel Spurs By Andre Norton

In 1866, only men uprooted by war had reason to ride into Tubacca, Arizona. So when Drew Rennie, newly discharged from Forrest's Confederate scouts, arrived leading everything he owned behind him--his thoroughbred stud Shiloh, a mare about to foal, and a mule--he knew his business would not be questioned. To anyone in Tubacca there could be only one extraordinary thing about Drew, and that he could not reveal: his name, Rennie.