Along the Golden Horn - Strolling Through Istanbul: The Classic Guide to the City - page 311

of the Mongols, Charabanda, but this time she refused; perhaps she
had had enough of Khans. At about this time Maria founded the
church which we see today, together with a convent, and dedicated it
to the Mouchliotissa, Our Lady of the Mongols. Maria, the Despoina
of the Mongols, as she was known, then became a nun and spent her
last years in retirement in her convent: This romantic tale appears
to be only partially true, for the church seems actually to have been
founded by Isaac Dukas, uncle of Michael VIII, about 1261.The
Despoina of the Mongols perhaps merely added to it and gave it
further adornments. After the Conquest, Sultan Mehmet II, at the
request of his Greek architect Christodoulos (who may be Atik Sinan,
the architect of the original Fatih Camii), issued a decree confirming
the right of the local Greeks to keep this church. The Greeks remain in
possession of the church to this day, and what is claimed to be Fatih's
ferman, or decree, is still displayed there. This is the only Byzantine
church which has been continuously in the hands of the Greeks since
before the Turkish Conquest.
The church was originally quatrefoil in plan internally and trefoil
externally. That is, the small central dome on a high drum was
surrounded by four semidomes along the axes, all but the western
one resting on the outer walls of the building, which thus formed
exedrae; the whole was preceded by a narthex of three bays. But the
entire southern side of the church was swept away in modern times
and replaced by a squarish narthex which is in every direction out of
line with the original building. The efect is most disconcerting. The
church is still adorned with one art treasure from its Byzantine period,
a very beautiful portative mosaic of the Theotokos Pammakaristos,
the All-Joyous Mother of God. The obvious similarity of this icon
to those we have seen at St. Nicholas and at the patriarchal church
of St. George strongly suggests that they were all done by the same
artist, working in the eleventh century. These are the only three such
portative mosaics remaining in the city, and there are only about ten
others still known to exist elsewhere.