The Church of Our Lady Panagiotissy is the only Church of Istanbul that has survived from Byzantine times, which has never served as a mosque and in which the divine liturgy has always been performed. Its inner walls are covered with icons from all over the city, some of which are of Byzantine origin. The founders of the convent on the site of the present church are the Venerable Evstoolia and Sosipatra (daughter of the emperor of Mauritius). In the XI century. a monastery of All Saints appeared near, many of whose inhabitants came from the Great Lavra on Mount Athos. During the years of Latin domination, the male monastery was abolished, and Isaac Duca, George Acropolitan’s father-in-law and the father of Michael the Restorer, resumed the women's monastery. In 1266, the church built at his expense was expanded and painted. In 1281, Michael's daughter, Maria Despina of Mongolia, widowed after the death of Persian Ilkhan Abaki, returned to Constantinople. It is to her that the monastery owes its present appearance and name. The heirs of Mary the Mongolian, however, did not pay due attention to the monastery and even transferred it as a pledge. In the fall of Constantinople, the near-campus became the site of the fiercest resistance to the invaders. This is reminiscent of the brick-red color of the plaster and the nickname “bloody church” given to the temple by the Turks. Under Sultan Selim I and Ahmed II, the church was tried to be turned into a mosque, but these plans did not come true. The Church of Mary of Mongolia remains the parish church of the Greek community of the Fatih district up to our days. Believers see the reason for this in the fact that Mehmed II himself allegedly handed over the temple to the care of the mother of the Greek architect Christodoulus in gratitude for the construction of the Fatih mosque. The church suffered during the Istanbul pogrom of 1955, but was restored.