By the beginning of the Christian era the idea of domestication of plants and livestock had spread to all but the remotest parts of the globe. But initially only indigenous plants were grown, and certain farming methods also remained confined to their regions of origin. Thus the plough probably had its origins in the Near East, and by the beginning of the Christian era was the basis of farming in the great agricultural civilizations of China, India and Europe. In Africa, however, the plough was unknown until brought by Europeans in the late nineteenth century, and still has limited use, except in the Mediterranean north and in South Africa. Nor were the plough or the wheel known in the Americas until after the arrival of Europeans in 1492.
Equally marked was the absence of sheep, cattle, pigs, chickens and horses from the New World. However, all were introduced into the Americas by Europeans and were spread rapidly throughout the continent (Isaac, 1970).