religious motives were active, but they were mingled on both sides with political considerations. The alienation of feeling on the part of the Roman bishops was one cause of the separation of Italy from the Greek Empire. LITERATURE AND CULTURE.--While there was a prevalence of illiteracy in the West, there continued in the Eastern Empire an interest in letters, and a respect for classical literature. Devoted Greek monks taught the Gospel to the _Bulgarians_ and to the Slavonian tribes on its borders. _Cyril_ and _Methodius_, faithful missionaries, gave the Bible to the _Moravians_ in their own tongue. In the seventh century, _John of Damascus_ compiled from the Greek Fathers a celebrated treatise on theology. But the period of original thought in theology, as elsewhere, had passed by. This work of the Damascene was made up chiefly of excerpts from the Fathers before him. In earlier days the church in the East had been served by erudite theologians of great talents and of great excellence, such as _Basil the Great_ (328-379), _Gregory of Nyssa, Gregory of Nazianzum_ (326-390); all of whom were liberal-minded men, strenuous defenders of orthodox doctrine, and yet not unfriendly to philosophical study. Of even wider fame was _John Chrysostom_ (347-407), a preacher of captivating eloquence and of an earnest Christian spirit, whose censure of the vices of the Byzantine court provoked the wrath of the Empress _Eudoxia_, and twice drove him into banishment. In the declining days of the empire, literary effort was mainly confined to compilations and comments. _Eusebius_, in the fourth century, had written a _History of the Church_, and a _Chronicle_, or General History; and, a century later (about 432), _Zosimus_ composed a _History_ in a spirit of antipathy to Christianity and of sympathy with the old religion. To _Procopius_ (who died about 565) we owe an interesting history of the times of _Justinian_. After the seventh century, all traces of life and spirit vanish from the pages of the Byzantine historians. In mathematics and astronomy, in architecture and mechanics, the Byzantine Greeks were the teachers of the Arabians and of the new peoples of the West. The Byzantine style of architecture was of a distinct type, and was widely diffused.