Christianity:
seized upon the arch as her own; decorated it, and delighted in it:
invented a new Doric capital to replace the spoiled Roman one: and all
over the Roman Empire set to work, with such materials as were nearest
at hand, to express and adorn herself as best she could. This Roman
Christian architecture is the exact expression of the Christianity of
the time, very fervid and beautiful--but very imperfect; in many
respects ignorant, and yet radiant with a strong, childlike light of
imagination, which flames up under Constantine, illumines all the
shores of the Bosporus and the AEgean and the Adriatic Sea, and then
gradually, as the people give themselves up to idolatry, becomes
corpse-like. The architecture sinks into a settled form--a strange,
gilded, and embalmed repose: it, with the religion it exprest; and so
would have remained forever--so does remain where its languor has been
undisturbed. But rough wakening was ordained for it.

The Christian art of the declining empire is divided into two great
branches, western and eastern; one centered at Rome, the other at
Byzantium, of which the one is the early Christian Romanesque,
properly so called, and the other, carried to higher imaginative
perfection by Greek workmen, is distinguished from it as Byzantine.
But I wish the reader, for the present, to class these two branches of
art together in his mind, they being, in points of main importance,
the same; that is to say, both of them a true continuance and sequence
of the art of old Rome itself, flowing uninterruptedly down from the
fountain-head, and entrusted always to the best workmen who could be
found--Latins in Italy and Greeks in Greece; and thus both branches
may be ranged under the general term of Christian Romanesque, an
architecture which had lost the refinement of pagan art in the
degradation of the empire, but which was elevated by Christianity to
higher aims, and by the fancy of the Greek workmen endowed with
brighter forms. And this art the reader may conceive as extending in
its various branches over all the central provinces of the empire,
taking aspects more or less refined, according to its proximity to the
seats of government; dependent for all its power on the vigor and
freshness of the religion which animated it; and as that vigor and
purity departed, losing its own vitality, and sinking into nerveless
rest, not deprived of its beauty, but benumbed, and incapable of
advance or change.