The history of the Gao Empire precedes that of the Songhai Empire in the region of the Middle Niger. Both empires had the town of Gao as their capital. Apart from some Arabic epitaphs on tombstones discovered in 1939 at the cemetery of Gao-Saney (6 km to the east of the city) there are no surviving indigenous written records that date from before the middle of the 17th century. Our knowledge of the early history of the town relies on the writings of Arabic geographers living in Morocco, Egypt and Andalusia, most of whom never visited the region. These authors referred to the town as Kawkaw or Kuku. The two key 17th century chronicles, the "Tarikh al-Sudan" and the "Tarikh al-fattash", provide information on the town at the time of the Songhai Empire but they contain relatively little on the social and economic history. The chronicles do not, in general, acknowledge their sources. Their accounts for the earlier periods are almost certainly based on oral tradition and for events before the second half of the 15th century they are likely to be less reliable. For these earlier periods, the two chronicles sometimes provide conflicting information.