Located around the corner from Istanbul University and close to the Valens Aqueduct, the church is believed to have been built in the 12th century on the site of a much older chapel, and was converted into a mosque during the Ottoman period. The eclectic interior features beautiful marble panels in an array of colors, Byzantine-style exposed brickwork, and a vaulted dome that was painted over during the Ottoman period. The two side chapels are, unfortunately, closed, and
frescoes found there that date to the Crusader occupation of Istanbul in the early 13th century have been moved to the Istanbul Archaeological Museum.
16 Mart Şehitleri Cad., Beyazıt, Istanbul, Turkey