The Founding of Baghdad

Caliph al Mansur founds the Round City on the Tigris, soon the largest and most learned city on earth.

Al Mansur chose a site where the Tigris and Euphrates draw near and built Madinat al Salam, the City of Peace, as a perfect circle with four gates facing the corners of the empire. Within a century Baghdad held perhaps a million people, its markets trading from China to Andalus and its libraries gathering the knowledge of every civilization.