course of the transition to Byzantine, the first mature Christian
style, cannot be satisfactorily traced while, guided by Roman
archaeologists, we continue to regard Rome as a source of Christian art
apart from the rest of the world. Christianity itself was not of Rome, it
was an eastern leaven in Roman society. Christian art even in that capital
was, we may say, an eastern leaven in Roman art. If we set the year 450 for
the beginning of Byzantine art, counting all that went before as early
Christian, we get one thousand years to the Moslem conquest of
Constantinople (1453). This millennium is broken into three well-marked
periods by the great iconoclastic schism (726-842) and the taking of
Constantinople by the Crusaders in 1204. The first we may call the
classical epoch of Byzantine art; it includes the mature period under
Justinian (the central year of which we may put as 550), from which it
declined until the settlement of the quarrel about images, 400 years in
all, to, say, 850. The second period, to which we may assign the limits
850-1200, is, in the main, one of orientalizing influences, especially in
architecture, although in MSS. and paintings there was, at one time, a
distinct and successful classical revival. The interregnum had caused
almost complete isolation from the West, and inspiration was only to be
found either by casting back on its own course, or by borrowing from the
East. This period is best represented by the splendid works undertaken by
Basil the Macedonian (867-886) and his immediate successors, in the
imperial palace, Constantinople. The third period is marked by the return
of western influence, of which the chief agency was probably the
establishment of Cistercian monasteries. This western influence, although
it may be traced here and there, was not sufficient, however, to change the
essentially oriental character of the art, which from first to last may be
described as Oriental-Christian.

_Architecture._--The architecture of our period is treated in some detail
in the article ARCHITECTURE; here we can only glance at some broad aspects
of its development. As early as the building of Constantine's churches in
Palestine there were two chief types of plan in use--the basilican, or
axial, type, represented by the basilica at the Holy Sepulchre, and the
circular, or central, type, represented by the great octagonal church once
at Antioch. Those of the latter type we must suppose were nearly always