A 10th-century Mosque
Mu’izz founded the mosque al-Azhar in Cairo in 970. What you see today is evidence of successive generations of rebuilding, which you can read about here.
A 15th-century Description
Maqrizi, an Egyptian historian, wrote one of the most important histories of the Fatimids in Arabic in the 15th century. Here, he explains how Cairo got its name.
Source, p. 78.