e size, and with
five arcaded porches at the western end that form one of the grandest
facades in the world. Numerous columns of many covered marbles uphold
graceful arches, the spandrels, or triangular spaces between them filled
in with gleaming mosaics, and above them rise other arches that contrast
well with tapering towers supported on slender pilasters to which the
domes beyond form an admirable background. Within the church to which
this magnificent narthex gives entrance, an infinite variety of
harmonious details combine to produce an entrancing effect: one charming
vista succeeding another, the whole flooded with light from a vast
number of windows, there being no less than eighty in the domes alone.
Mosaics of different dates and greatly varying aesthetic merit completely
clothe the surfaces of the vaulting, the capitals of the columns--many
of which, by the way, are purely decorative, upholding no arches--are
elaborately carved, and the flooring is of marble, slabs of considerable
size being set in patterns of tesserae.

In the various countries which fell under the influence of the followers
of Mahommed a style of architecture was evolved that had marked
affinities with the Byzantine, the first mosques having been designed,
it is supposed, by Christian architects of Oriental origin, who retained
the square or circular ground-plan of early churches, though they
modified the interior to suit the requirements of the new religion,
introducing, for instance, a central tank for ablutions. Mosques
intended for worship only, generally had flat roofs, the use of the dome
being at first distinctive of a burial place, but as it very soon became
usual to inter in mosques, the dome came to be quoted as a distinctive
feature of them. By degrees simple unadorned mosques were replaced by
vast buildings with many arcaded courts entered from ornate lateral
doorways, whilst certain characteristic features were introduced, of
which the chief were the stalactite vaulting, the name of which explains
itself, the horse-shoe arch, and the minaret, the last named a turret of
several stories gradually decreasing in circumference, each with a
balcony of its own from which the mueddin calls the faithful to prayer.
Pointed arches were also constantly employed as well as the form known
as cusped, that is to say one with a triangular projection springing
from the inner curve. A minor but most significant characteristic of
Saracenic architec