Horse racing - history
Historically, equestrians honed their skills through games and races. Equestrian sports provided entertainment for crowds and honed the excellent horsemanship that was needed in battle. Horse racing of all types evolved from impromptu competitions between riders or drivers. All forms of competition, requiring demanding and specialized skills from both horse and rider, resulted in the systematic development of specialized breeds and equipment for each sport.Chariot racing was one of the most popular ancient Greek, Roman and Byzantine sports. Chariot racing was often dangerous to both driver and horse as they frequently suffered serious injury and even death, but generated strong spectator enthusiasm. In the ancient Olympic Games, as well as the other Panhellenic Games, the sport was one of the most important equestrian events. Horse racing was also a part of myth and legend, such as the contest between the steeds of the god Odin and the giant Hrungnir in Norse mythology.
The popularity of equestrian sports through the centuries has resulted in the preservation of skills that would otherwise have disappeared after horses stopped being used in combat.
Thoroughbred
There are three founding sires that almost all Thoroughbreds can trace back to: the Darley Arabian, the Godolphin, and the Byerly Turk, named after their respective owners, Thomas Darley, Lord Godolphin, and Captain Robert Byerly. All were taken to England where they were mated with racing mares. Thoroughbreds range in height, and are measured in hands (a hand being four inches). Some are as small as 15 hands while others are over 17 hands. Thoroughbreds can travel medium distances at fast paces, requiring a balance between speed and endurance.
Source: www.en.wikipedia.org