The Sao people are one of the oldest civilizations of West Africa. According to a Toubou tradition, the Sao originally come from a region about 500 kilometers north of Lake Chad. In the 7th century, they lived in the Bilma, Tadjeré and Fatchi oases.

Between 930 and 970, they are reported to have been living to the south of Lake Chad, in a plain regularly flooded by rain. The Sao Empire would be founded there. The Sao would certainly have had contact with the indiginous people of the region and interbred. Carbon-14 dating done by J.-P. Leboeuf seems to prove that there were humans occupying this region, as early as 425 B.C.

Settlement in this region happened in three distinct and successive migrations. The first, by hunters armed with spears, accompanied by their hunting dogs. The second was also a migration of hunters, but this time, armed with bows and arrows. The third, and final, was by fishermen equipped with nets, coming, undoubtedly, to the very edges of the lake... Without archaeological details, the evidence of movements is not precise, nor does it make distinctions between these various groups. The Sao are thus a group of various similar ethnic tribes, all undoubtedly non-Muslim.

In the 11th century, the Sao, who were great architects, built large cities surrounded by dry earth walls complete with fortifications and ramparts.

The Sao - the term means "the men from another time" - acquired considerable political power. They encroached upon the Kingdom of Kanem, which is located in eastern Chad and populated by the Kanuri.

This encroachment began numerous wars between the two camps, one alternatively winning and losing, until the Boulala, of Yemeni origin, finally seized Kanem, with the combined forces of the Kanembu and the Kanuri definitively driving the Sao out of the area in the 16th century. This would be the end of the Sao Empire. The survivors would later be killed by either the Massa, or the Bornu troops who decimated the remaining cities. The very last Sao finally fled and took refuge in north-western Cameroon. There, they integrated with the Massa population already living in this area. Together, they formed a new ethnic group: the Kotoko. At the end of the 17th century and the beginning of the 18th century, the Sao ceased to exist as a people...