bly due to the
adaptation of the chapel to the position of the residence with which it
was associated. The masonry is very fine and regular, built in courses
of squared stone alternating with four courses of brick, all laid in
thick mortar joints, and pierced with numerous putlog holes running
through the walls. It presents a striking likeness to the masonry in the
fortifications of the city. The lower story is an oblong hall covered
with a barrel vault, and terminates in an arch and apse. In the west
side of one of the jambs of the arch is a small niche. The vault for
one-third of its height is formed by three courses of stone laid
horizontally and cut to the circle; above this it is of brick with
radiating joints. Here cows are kept.

The upper story is m. 3.75 above the present level of the ground. It is
a single hall m. 8.80 in length and m. 3.70 wide, terminating in a bema
and a circular apse in brick. Over the bema is a barrel vault. A dome,
without drum or windows, resting on two shallow flat arches in the
lateral walls and two deep transverse arches strengthened by a second
order of arches, covers the building. In the wall towards the north-west
there is a window between two low niches; and a similar arrangement is
seen in the opposite wall, except that the door which communicated with
the residence occupies the place of the window. The apsidal chambers,
usual in a church, are here represented by two niches in the bema.
Externally the apse shows five sides, and is decorated by a flat niche
pierced by a single light in the central side, and a blind concave
niche, with head of patterned brickwork, in the two adjacent sides. The
dome, apse, vaults, and transverse arches are in brick, laid in true
radiating courses. The absence of windows in the dome is an unusual
feature, which occurs also in the angle domes of S. Theodosia. The
pendentives are in horizontal courses, corbelled out to the centre, and
at each angle of the pendentives is embedded an earthenware jar, either
for the sake of lightness, or to improve, as some think, the acoustics
of the building. This story of the chapel is used as a hayloft.

A careful survey of the building shows clearly that the domical
character of the chapel is not original, and that the structure when
first erected was a simple hall covered with a wooden roof. Both the
shallow wall arches and the deep transverse arches under the dome are
insertions in the walls of an older fabric.