By the time humans began to keep written records, horse racing was an organized sport in all major civilizations from Central Asia to the Mediterranean. Both chariot and mounted horse racing were events in the ancient Greek Olympics by 638 BC, and the sport became a public obsession in the Roman Empire.
The origins of modern racing lie in the 12th century, when English knights returned from the Crusades with swift Arab horses. Over the next 400 years, an increasing number of Arab stallions were imported and bred to English mares to produce horses that combined speed and endurance. Matching the fastest of these animals in two-horse races for a private wager became a popular diversion of the nobility.
Horse racing began to become a professional sport during the reign (1702-14) of Queen Anne, when match racing gave way to races involving several horses on which the spectators wagered. Racecourses sprang up all over England, offering increasingly large purses to attract the best horses. These purses in turn made breeding and owning horses for racing profitable. With the rapid expansion of the sport came the need for a central governing authority. In 1750 racing's elite met at Newmarket to form the Jockey Club, which to this day exercises complete control over English racing.
The Jockey Club wrote complete rules of racing and sanctioned racecourses to conduct meetings under those rules. Standards defining the quality of races soon led to the designation of certain races as the ultimate tests of excellence. Since 1814, five races for three-year-old horses have been designated as "classics." Three races, open to male horses (colts) and female horses (fillies), make up the English Triple Crown: the 2,000 Guineas, the Epsom Derby (see DERBY, THE), and the St. Leger Stakes. Two races, open to fillies only, are the 1,000 Guineas and the Epsom Oaks.
The Jockey Club also took steps to regulate the breeding of racehorses. James Weatherby, whose family served as accountants to the members of the Jockey Club, was assigned the task of tracing the pedigree, or complete family history, of every horse racing in England. In 1791 the results of his research were published as the Introduction to the General Stud Book. From 1793 to the present, members of the Weatherby family have meticulously recorded the pedigree of every foal born to those racehorses in subsequent volumes of the General Stud Book. By the early 1800s the only horses that could be called "Thoroughbreds" and allowed to race were those descended from horses listed in the General Stud Book. Thoroughbreds are so inbred that the pedigree of every single animal can be traced back father-to-father to one of three stallions, called the "foundation sires." These stallions were the Byerley Turk, foaled c.1679; the Darley Arabian, foaled c.1700; and the Godolphin Arabian, foaled c.1724.