Fodor's Expert Review Church of Saint Mercurius
Yet another Roman legionary, Mercurius, or Abu Sayfayn ("of the two swords"), dreamed one night that an angel gave him a glowing sword and ordered him to use it to fight paganism. He converted to Christianity and was martyred in Palestine. His remains were brought to Cairo in the 15th century.
This site is of great importance to Coptic Christians. It was the cathedral church of Cairo, and when the seat of the Coptic Patriarch moved from Alexandria to Cairo, Saint Mercurius was the chosen location. The complex actually contains a monastery, a convent, and three churches: Abu Sayfayn, Abna Shenouda, and a church of the Virgin.