The Fifth and Sixth Hills - Strolling Through Istanbul: The Classic Guide to the City - page 266

The side chapel has been most beautifully restored, its missing
columns replaced, and its mosaics uncovered and cleaned. The mosaics
of the dome have always been known, for they were never concealed,
but they now gleam with their former brilliance: the Pantocrator
surrounded by 12 Prophets; in the apse Christ “Hyperagathos” with
the Virgin and St. John the Baptist; other surfaces contain angels
and full-length figures of saints. Only one scene mosaic survives: the
Baptism of Christ. Though much less in extent and variety than the
mosaics of Kariye Camii (see Chapter 14), these are nevertheless an
enormously precious addition to our knowledge of the art of the last
renaissance of Byzantine culture in the early fourteenth century.
The Church of the Pammakaristos remained in the hands of the
Greeks for some time after the Conquest; in fact, in 1456 it was
made the seat of the Greek Orthodox Patriarchate after the Patriarch
Gennadius abandoned the Church of the Holy Apostles. It was in
the side-chapel of the Pammakaristos that Mehmet the Conqueror
came to discuss questions in religion and politics with Gennadius.
The Pammakaristos continued as the site of the Patriarchate until
1568; five years later Murat III converted it into a mosque. He then
called it Fethiye Camii, the Mosque of Victory, to commemorate his
conquest of Georgia and Azerbaijan.
CHURCH OF ST. JOHN IN TRULLO
Returning to Fethiye Caddesi we follow it in the same direction for a
short distance and then take the first turning on the right. We there
find ourselves face to face with a charming little Byzantine church
which has recently been restored. It is called Ahmet Paşa Mescidi
and has been identified with almost virtual certainty as the Church
of St. John the Baptist in Trullo. Nothing whatever is known of
the history of the church in Byzantine times. Three years after the
Conquest, in 1456, when Gennadius transferred the Patriarchate
to the Pammakaristos, he turned out the nuns there ensconced and
gave them this church instead. Here they seem to have remained
until about 1586, when the church was converted into a mosque
by Hirami Ahmet Paşa, from whom it takes its Turkish name. The
tiny building was a characteristic example of the four-column type