This is the negative underbelly of horse racing, but the history of breeding stretches back almost as far as the domestication of horses in about 4500 BCE. The Bedouin, along with other Middle Eastern and Asian nomads, have been breeding horses for thousands of years. The Bedouin have even passed down pedigrees for their Arabian horses that go as far back as 1330. During the Middle Ages, Europeans bred large, strong horses for their ability to carry a heavily armored knight. Thoroughbreds, such as the horses in this video, were first bred in the year 1700 with the express purpose of horse racing. Although the breed began in England, Lexington, Kentucky had established its place as the heart of thoroughbred breeding by the late 18th century.