the dome were,
however, removed when the building was converted into a mosque in
Turkish times, and have been replaced by two large pointed arches which
span the entire length of the church. But the old wall arches of the
dome-columns are still visible as arched piercings in the spandrils of
the Turkish arches. A similar Turkish 'improvement' in the substitution
of an arch for the original pair of columns is found in the north side
of the parecclesion attached to the Pammakaristos (p. 152). The dome
with its eight windows is likewise Turkish. The windows are lintelled
and the cornice is of the typical Turkish form. The bema is almost
square and is covered by a barrel vault formed by a prolongation of the
eastern dome arch; the apse is lighted by a lofty triple window. By what
is an exceptional arrangement, the lateral chapels are as lofty both on
the interior and on the exterior as is the central apse, but they are
entered by low doors. In the normal arrangement, as, for instance, in
the Myrelaion, the lateral chapels are low and are entered by vaults
rising to the same height as those of the angle chambers, between which
the central apse rises higher both externally and internally.

The chapels have niches arched above the cornice on three sides, and are
covered by cross-groined vaults which combine with the semicircular
heads of the niches to produce a very beautiful effect. To the east they
have long bema arches flanked by two small semicircular niches, and are
lighted by small single windows.

The church is preceded by a narthex in three bays covered by
cross-groined vaults supported on strong transverse arches. At either
end it terminates in a large semicircular niche. The northern one is
intact, but of the southern niche only the arched head remains. The
lower part of the niche has been cut away to afford access to the
narthex of the south church. This would suggest that, at least, the
narthex of the south church is of later date than the north church.

Considered as a whole the north church is a good example of its type,
lofty and delicate in its proportions.

_The South Church._--The narthex is unsymmetrical to the church and in
its present form must be the result of extensive alteration. It is in
two very dissimilar bays. That to the north is covered with a
cross-groined vault of lath and plaster, probably on the model of an
original vault constructed of brick. A door in the eastern wall leads to
the north