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.