qasr al-sham‘ (the Fortress of Candles), name given by the Arabs to the Roman fortress of Babylon following the arab conquest of egypt. According to al-maqrizi, candles burned every month at the top of the tower of the fortress when the sun entered a new constellation of the zodiac. This conveyed the event to the population. In time Qasr al-Sham‘ came to designate a whole quarter of Old Cairo inhabited mainly by Copts.
Four Coptic churches are still to be found in that part of Cairo: Church of al-Mu‘allaqah, Church of Abu Sarjah (Saint Sergius), Church of Sitt Barbarah (Saint Barbara), and Church of Mar Jirjis (Saint George). A fifth church, known as Qasriyyat al-Rihan (Church of Our Lady), burned down in 1979.