Apart from some Arabic epitaphs on tombstones discovered in 1939 at the cemetery of Gao-Saney (6 km to the east of the city)[2] there are no surviving indigenous written records that date from before the middle of the 17th century.

[3] Our knowledge of the early history of the town relies on the writings of Arab geographers living in Morocco, Egypt and Andalusia, most of whom never visited the region.

Using the epitaphs as a primary source, modern scholars increasingly question whether the chronicles, as biased political documents, are useful at all for describing the period of the Gao Empire.

[7] Twentieth-century historians saw Gao as relatively unimportant compared with the roughly contemporary Ghana Empire, but the 2018 study African Dominion argued that Gao was West Africa's first city-state, providing a key model for the Ghana Empire and subsequently the Mali and Songhay empires, and that the Middle Niger region that it dominated was economically and politically interconnected with the Sahel, the Savannah, and the Middle East in ways that made it an important part of the world system.

He has a town on the Nile [Niger], on the eastern bank, which is called Sarnāh, where there are markets and trading houses and to which there is continuous traffic from all parts.

[22] The Ta’rīkh as-sūdān's ruler-list has the ruler Kusuy-Muslim converting to Islam in 1009–10, and a 1068 report by al-Bakrī that Gao's kings were Muslim but most of their subjects at that time were not.

By the middle decades of the century, the Almoravids had become a significant power in West Africa, spreading their interpretation of Sunni Islam.

[28] The Zaghe married women from the previous royal line, and the queens of the time held significant political power and may have even been the head of matrilineal kin groups.

[32] Archaeological evidence, however, shows that they likely took refuge downstream, as the architectural and epigraphic styles common in independent Gao up until the late 1200s continued to be used in Kukiya until the time of Sonni Ali (1464–1492).

Craftspeople fashioned carnelian into beads, which are dated as early as the third century, and which were greatly valued in the Sudan and West African rainforest.

[14] Relative to its peers in Kanem and Wagadu, Gao was not a major center of the slave trade, although slavery was widely practiced domestically.

The bed of the Wadi Gangaber passes to the south of the Gao-Saney occupation mound (tell) but to the north of Gao Ancien.

[43] Archaeological digs have determined that Gao Ancien was the political center, containing the oldest royal palace discovered in the region.