Appendices - Strolling Through Istanbul: The Classic Guide to the City - page 475

Abdül Mecit I, 1839-61
Abdül Aziz, 1861-76
Murat V, 1876
Abdül Hamit II, 1876-1909
Mehmet V, 1909-18
Mehmet VI, 1918-22
Abdül Mecit (II) (Caliph only), 1922-4
NOTES ON BYZANTINE ARCHITECTURAL FORMS
The earliest buildings to be used as churches in the ancient world
were chiefly of two types: the basilica and the centralized building.
The basilica, developed in Hellenistic and Roman times for a variety
of public purposes, was for several centuries the plan most widely
adopted for ordinary churches. It is a long rectangular building divided
by two rows of columns into three parts, a wide central nave flanked
by an aisle on each side; at the east end of the nave is a semicircular
projection or apse . The entrance, at the west and opposite the apse,
is generally preceded by a vestibule or narthex , which in turn opens
into a large arcaded courtyard or atrium . Dozens of early examples
of this plan are to be found in all parts of the Roman Empire, but in
Istanbul only one pure basilica has survived, the church of St. John
of Studius, built in 449-50, now partly ruined, but whose basilical
structure is still clearly visible.
The early basilicas had pitched roofs and flat ceilings. Later, chiefly
in the reign of Justinian, an innovation was made by introducing a
dome. Two ancient examples in Istanbul survive intact: Haghia Eirene
and Haghia Sophia. The nave of the former is covered at the east by a
large dome, at the west by a smaller, slightly elliptical domical vault;
otherwise it is a very typical basilica. In Haghia Sophia the enormous
central dome is supported to east and west by two semidomes of equal
diameter and there are other modifications which to a superficial view
conceal its essentially basilical plan.
The other type of classical building sometimes used for churches
was of a centralized plan , round or polygonal. In Istanbul there
remain the very scanty ruins of a few such buildings of a very early
period, but the most famous and beautiful is somewhat later in date,