The Darley Arabian was one of three dominant foundation sires of modern Thoroughbred horse racing bloodstock. The other two founders were the Godolphin Arabian and the Byerley Turk. This bay Arabian horse was bought in Aleppo, Syria, by Thomas Darley in 1704 and shipped to Aldby Park in England, as a present for his brother.

The Thoroughbred is a horse breed developed for horse racing. Although the word thoroughbred is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are considered "hot-blooded" horses that are known for their agility, speed, and spirit.