non-wild stallions

The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. Horses first evolved in the Americas, but went extinct there until reintroduced by Europeans. Horses have long been among the most economically important domesticated animals and are prominent in religion and mythology. The horse has played an important role as transportation, as a source of food, fuel, and clothing, and as a weapon. While isolated domestication may have occurred as early as 10,000 years ago, the first clear evidence dates to c. 5000 BC, and becomes widespread only after 2000 BC. Selective breeding since that time has produced numerous breeds. Some have been bred so that they can be ridden, usually with a saddle, while other breeds can be harnessed to pull objects like carriages or plows. In some societies, horses are a source of food, both meat and milk; in others it is taboo to consume them. In industrialized countries horses are predominantly kept for leisure and sporting pursuits, while they are still used as working animals in many other parts of the world.

Competing theories exist as to the time and place of initial domestication. The earliest evidence for the domestication of the horse comes from Central Asia and dates to approximately 4,500 BC. Archaeological finds such as the Sintashta chariot burials provided unequivocal evidence that the horse was definitely domesticated by 2000 BC.

from Wikipedia