Organized horse racing in the United States dates back to 1665, when Richard Nicolls, the royal governor of New York, authorized the first track at what is now Hempstead, Long Island. The first thoroughbred or purebred sire of record to reach the country was Bulle Rock, imported from England to Virginia around 1730. Thereafter scores of both sires and mares arrived, forming the foundation of the American racing stock, which by the 1860s was based on Diomed, the winner of the first English Derby, Glencoe, winner of the Two Thousand Guineas and Ascot Gold Cup, and others. During the colonial era horse racing was the favorite pastime of the Southern elite, especially the Virginian gentry. In the late 1820s track organizers in the United States standardized weights, planned yearly schedules, arranged the settlement of bets, and fixed rules of entry. Local clubs increasingly charged admission, less...