Around Beyazit and Sehzadebas - Strolling Through Istanbul: The Classic Guide to the City - page 179

külliye, though clearly baroque in detail, has a classic simplicity which
recalls that of the Köprülü complex on the Second Hill.
BODRUM CAMİİ (CHURCH OF THE MYRELAION)
We now continue along Ordu Caddesi and take the second turning
on the left, just opposite Laleli Camii. We then turn right at the next
corner and at the end of this street ascend a flight of steps onto a large
marble-paved terrace. Just beyond the far left corner of the terrace
we see a former Byzantine church known locally as Bodrum Camii,
or the Basement Mosque, because of the crypt that lies beneath it.
The building was excavated in 1964-6 by Professor Cecil L. Striker
of the University of Pennsylvania, who identified the church as the
Myrelaion, “the place of the sacred myrrh”, built by the Emperor
Romanus I Lecapenus (r. 919-44) at the beginning of his reign along
with a monastery of the same name. Beneath the church he built a
funerary chapel, where he interred his wife Theodora after she died
in 922. Next to the church and monastery Romanus also erected a
palace on the substructure of an earlier Roman edifice, known as
the Rotunda, beneath the marble terrace we see today. The church
was converted into a mosque late in the fifteenth century by Mesih
Pasha, a descendant of the Palaeologues who converted to Islam and
led the forces of Mehmet II in their first and unsuccessful attack on
Rhodes in 1480. The building was several times gutted by fire and
was restored in 1965-6, along with the chapel beneath it, and it is
once again serving as a mosque, while the Rotunda has been rebuilt
as a subterranean shopping mall, with its entrance on the south side
of the terrace opposite the mosque.
The most distinctive aspect of the exterior of the Myrelaion is the
array of half-cylindrical buttresses that project from the west façade
and the sides of the narthex and naos, articulating the internal bay
divisions. The dome sits on a high cylindrical drum penetrated by
eight round-arched windows. The church and the funerary chapel
beneath it are of the same design, namely the four-column type so
common in the tenth and eleventh centuries, with a three-bay narthex
to the west and to the east the apse flanked by the sacristy and the
prothesis, the chapel where the Eucharist was kept.