The Church of Hagia Sophia, associated with one of the greatest creative ages of man, was also the Cathedral of the Ecumenical Patriarchate of Constantinople for more than one thousand years. Originally known as the Great Church.

The church of Hagia Eirene was never converted into a mosque. Since, however, it stood within the enclosure of the Saray and next to the barracks of the Janissaries it served for a long time as an arsenal. In 1846 it became a Museum of Antiquities and in 1874 a Military Museum.

In 1587, Sultan Murad III (1574-1592), converted the church of St. Mary Pammakaristos into a mosque and called it Fethiye (= Victory) Camii, to commemorate the conquest of Georgia and Azerbaijan. The Patriarchate and its sacred relics and vessels were then transferred in Theotokos Paramythia.

The Church of the Holy Savior of Chora, called in Turkish, Kariye Camii, is after Hagia Sophia the most interesting Byzantine church in the city. Not so much for the building itself, pretty as that is, as because of the superb series of mosaics and frescoes.

The monastery of St. John of Studius is one of the most famous monasteries of Byzantium. A center of culture and learning, it was also -an eminent and renowned school of virtue- where some of the greatest scholars of the Byzantine era studied and taught.

The basement-crypt has probably given to the monastery the name of Bodrum Camii, when it was converted into a mosque in 1574 under Murad III. Makridis reports that a fine portrait of a princess discovered during excavations at the south side of the crypt is now missing.

Recent research has identified the present-day Kilise Camii with the church of the Sts. Theodoroi. Paspatis and Janin mention another church, known from sources as St. Theodore Sphorakiou, originally built in the 5th century. The ruins of this church, had survived till the 19th century.

The monastery of Lips has been identified with certainty with the Fenari-lsa Camii (Mordtmann, Millingen, Makridis, Janin). It is a building complex composed of the church of the Theotokos Panachrantos (the Immaculate Mother of God) the church of St. John the Baptist and the funerary chapel.