Most horse breeds have been bred for a specific reason; the thoroughbred racehorse was bred to run. Thoroughbreds originate from the Arabian breed, and all thoroughbreds can be traced back to three original sires (fathers): The Byerley Turk, The Darley Arabian, and The Godolphin Arabian. Thoroughbreds are known for their speed, and also for their jumping ability, used in steeplechases and in show jumping and other horse activities. Although thoroughbreds generally are slightly temperamental, they are very trainable and loyal. 