Along the Golden Horn - Strolling Through Istanbul: The Classic Guide to the City - page 317

ATİK MUSTAFA PAŞA CAMİİ
About 150 metres farther along on Mustafa Paşa Bostanı Sokağı we
turn right on a short street that leads out to the Golden Horn. Near
the end of the street we see on the right a pretty little Byzantine
church converted into a mosque known as Atik Mustafa Paşa Camii.
This has been identified tentatively as the Church of SS. Peter and
Mark.
The building appears to be the only cross-domed Byzantine church
of the ninth century remaining in the city. The wooden porch, the
dome and its drum, and probably some of the roofs and many of the
windows are Turkish restorations. For the rest, the church preserves
its original plan which is simple and, for a Byzantine structure,
regular. A dome, doubtless originally on a fairly high drum with
windows, covers the centre of the cross; the arms are barrel-vaulted,
as are the four small rooms beyond the dome piers which fill up the
corners of the cross; they are entered through high, narrow arches.
The three apses, semicircular within, have three faces on the exterior.
It must have been an attractive little church and it still has a decayed
charm.
BLACHERNAE AYAZMA
We now return to Mustafa Paşa Bostanı Sokağı and continue on in the
same direction as before. At the next corner on the left we come to the
entrance of the famous ayazma , or holy spring, of Blachernae. This
ayazma , like countless others in the city and elsewhere in the Greek
world, has been venerated since pre-Christian times, and its waters
are believed to possess miraculous powers. The ayazma at Blachernae
was one of the most popular in the city and even the Emperor and
Empress came here to partake of the life-giving waters. In 451 a great
church was built over the spring by Pulcheria, wife of the Emperor
Marcian. A few years later the church served to house the celebrated
robe and mantle of the Virgin. These garments, which had been stolen
from a Jewess in Jerusalem by two Byzantine pilgrims, were considered
to be the most sacred relics in Constantinople, “the palladium of the
city and the disperser of all warlike foes.” Thus Blachernae became
the most important shrine in the city and remained so throughout