Horse races, today popular throughout most of the Western world as well as in other areas, were probably contested as early as 1500 B.C. in Egypt. The roots of harness racing extend back at least to early Greece, where chariot races were a part of the Olympic games. In the Roman era the chariot race became an entertainment for the masses; the Circus Maximus seated over 200,000 spectators. The constant and widespread desire for faster and stronger horses for work, military use, and sport led to the development of several specially bred strains.
In 12th-century England, Henry II mated the offspring of the speedy Arabian stallions bred in the 9th–11th cent. with his own powerful mares. The resultant breed drew proud owners into informal wagers and races to determine the superior horses and riders. The first public racecourse opened at London about 1174, and the "sport of kings" became a staple of fairs. As early as the 16th cent., prizes were awarded in English racing, but the 12th Earl of Derby originated (1780) the first event held on a sweepstakes basis (whereby the winner "sweeps" the stake offered) at his estate in Epsom; known as the Epsom Derby or English Derby, it continues to be held annually.
In the American colonies, horse racing's appeal was evident in the 17th cent. Informal races, often held on busy roads, gave way by century's end to formal contests at racetracks. Although racing waned during the Revolutionary period, it regained popularity afterward, and in 1823 a North-South challenge drew 60,000 spectators to Long Island's Union Course (N.Y.) for a contest of three four-mile heats between two horses.