Al-Nasir Muhammad built his famous mosque in the Citadel during his third and longest reign (1309 through 1340 AD).
The Mosque of Sultan al-Nasir Muhammad was the royal mosque of both the Citadel and
Cairo itself, for it was here that the sultans of Cairo performed their Friday prayers, except on religious feasts, when prayer took place in a large gathering at the hippodrome beneath the Citadel walls. The mosque was large enough to hold as many as five thousand worshippers. The main entrance to the mosque is across the road from the entrance to the courtyard of Muhammad 'Ali's Mosque.
The position of the two minarets and two asymmetrically located portals are dictated by the orientation and location of the mosque, which faces the northern enclosure of the Citadel on one side with its official and military buildings, and adjoins the residences of the sultan on the west and south.
The interior of the mosque follows the hypostyle scheme with the standard pattern of a rectangular courtyard, a sanctuary on the qibla side and arcades surrounding its other three sides.
Within the mosque, the walls supported by the arcades have a row of arched windows that give the building a special character. These windows must have been added when the roof was raised. The openings help reduce the thrust carried by the arches, admit light and are ornamental as well. The voussoirs of the mosque's arcades are composed of ablaq masonry of the same stone, but painted. The ceiling over the arcades is flat and coffered with traces of its light blue and silver decorations still visible.
A special collection of pre-Islamic capitals crowns the marble columns of the mosque. The two pairs of
Coptic Christian capitals at the main entrance are particularly interesting. Their white marble is carved with a basket pattern. However, there are also capitals dating to the Greek and Roman periods.
