The mosque of Sultan Nasir ebn Kalaoun, which stands at the centre of Cairo citadel, although one of the most interesting in the city, seems to have received less attention than it deserves. This is probably due to the fact that, for many years past, it has ceased to be used as a mosque, and has been thrown into the background by the great Mosque of Mohamed Ali Pasha, which is visited by at least a thousand persons for every one who takes the trouble to enter the old royal mosque of the citadel.