The Church of Saint Mary of the Mongols is an Orthodox church in Istanbul. The name of the church in Turkish is known as Kanli Kilise (meaning Bloody Church). It is the only church from the Byzantine period in Istanbul that was not converted into a mosque during the Ottoman period and was left to the worship of Greeks.
The church has its origins in a monastery built in the early 7th century by Princess Sopatra, daughter of the Byzantine emperor Maurikios. However, after the Fourth Crusade, the monastery was destroyed during the Latin Empire. When the city was captured by the Byzantines again in 1261, a simple monastery was built in the same place by Isaac Doukas. Later, in 1281, Maria Despina Palaiologina, wife of the Mongol Ilkhanid ruler Abaka Khan, had the monastery and church built in their current form and received the title "Ktetorissa". From this date on, the church received the name "Mouchliotissa".
After the conquest of Istanbul in 1453, the Church was awarded by Mehmed the Conqueror, and donated to the family of Christodoulos, the architect of the Fatih Mosque. Mehmed the Conqueror made a request to Christodoulos for his labor in the construction of the mosque, and he wanted the church where he worshiped with his mother to always remain a church. With the decree issued by Mehmed the Conqueror, the existence and function of the church continued.
This historical structure, which has survived to this day, holds an important place in the cultural and religious heritage of Istanbul.