The first mosque on the site is said to have been built by 'Amr ibn al-'As in 641-42. 'Amr was the chief commander of the Arab troops who won Egypt for Islam and so the building has an historical significance beyond the surviving architecture. Although the remains of this earliest mosque have not survived, there are several historical accounts from which the design of the building can be reconstructed. It consisted of a rectangular structure 29 by 17 m without a concave mihrab and was probably built of mud brick and palm trunks.

Thirty-two years later in 673 the first mosque was pulled down and a larger structure built to accommodate the growing number of Muslims. As well as being larger the new mosque was equipped with four towers which could be used for the call to prayer. These have been interpreted as the first minarets although it is likely that they were not much higher than the roof of the mosque.

The earliest mosque from which any remains survive belongs to the reconstruction of 827 carried out by 'Abd Allah Ibn Tahir. The remains comprise the southern wall of the present mosque which contains blocked-up windows alternating with round-arched niches with shell-like hoods. Both niches and windows are framed by engaged colonettes. Internally there are remains of wooden cornices carved in late Hellenistic style which joined the end columns of the arcades to the wall. Descriptions of the mosque in the tenth century describe it as having glass mosaics on the wall and a bayt al-mal, or treasury, in the centre of the courtyard which together with the four towers suggest a resemblance to the Great Mosque of Damascus. In later periods several reconstructions and restorations were carried out. The most important changes include those made by Khalif Hakim who added two arcades in the sahn and had the mosaics removed, Sultan Baybars who rebuilt the north wall, the merchants whose restorations were carried out in 1401-2, Murad Bey who strengthened the building and added two minarets in 1797-8. In the restorations of Muhammad Ali in the 1840s the mosque achieved its present form. [hide description]