Man's earliest civilizations developed in Mesopotamia and Egypt between 3500 and 3000 BC.

The Indus valley followed soon afterwards, and at a later date a farming population emerged along the Yellow River in China.

In the North the wide grasslands of the steppes provided a feeding ground for the herds of the Nomads. The mobility of the warlike Nomads provided them with an advantage in any military confrontation with the richer farming communities further south.

The subsequent history of Eurasia became a contest between the superior military ability of the Nomads in the North, and the superior numbers of people made possible by farming in the South.