Frequently visited and recorded by 19th-century scholars and travelers, the building is sometimes identified as the church of St. Theodore, based on the 16th-century account of Pierre Gilles, who noted a church of that dedication somewhere in this area. At present the conservative Islamist community has made the building virtually inaccessible. One of the best preserved Byzantine churches in the capital, the building was studied by M.I. Nomides in 1937-38, but the results of this work were only recently published by C. Mango. These include the discovery of vaulted tombs beneath of the floor of the Palaiologan outer narthex. The outer narthex mosaics were partly uncovered at that time, but they have never been properly studied. The dating is not entirely certain, ranging between the 1290s and the 1320s. In 1979, the mosaics were whitewashed and have remained covered ever since.