Among theologians after John of Damascus must be mentioned: the emperor Leo VI., the Wise (886-911), who wrote numerous homilies and church hymns, and Theodorus of Studium (759-826), who in his numerous writings affords us instructive glimpses of monastic life. Pre-eminent stands the figure of the patriarch Photius. Yet his importance consists less in his writings, which often, to a remarkable extent, lack independence of thought and judgment, than in his activity as a prince of the church. For he it was who carried the differences which had already repeatedly arisen between Rome and Constantinople to a point at which reconciliation was impossible, and was mainly instrumental in preparing the way for the separation of the Greek and Latin Churches accomplished in 1054 under the patriarch Michael Cerularius. In the 11th century the polyhistor Michael Psellus also wrote polemics against the Euchites, among whom the Syrian Gnosis was reviving. All literature, including theology, experienced a considerable revival under the Comneni. In the reign of Alexius I. Comnenus (1081-1118), Euthymius Zigabenus wrote his great dogmatic work, the _Dogmatic Panoply_, which, like _The Fountain of Knowledge_ of John of Damascus in earlier times, was partly positive, furnishing an armoury of theology, partly negative and directed against the sects. In addition to attacking the dead and buried doctrines of the Monothelites, Iconoclasts, &c., to fight which was at this time a mere tilting at windmills, Zigabenus also carried on a polemic against the heretics of his own day, the Armenians, Bogomils and Saracens. Zigabenus's _Panoply_ was continued and enlarged a century later by the historian Nicetas Acominatus, who published it under the title _Treasure of Orthodoxy_. To the writings against ancient heresies were next added a flood of tracts, of all shapes and sizes, "against the Latins," i.e. against the Roman Church, and among their authors must also be enumerated an emperor, the gifted Theodore II. Lascaris (1254-1258). The chief champion of the union with the Roman Church was the learned Johannes Beccus (patriarch of Constantinople 1275-1282). Of his opponents by far the most eminent was Gregory of Cyprus, who succeeded him on the patriarchal throne. The fluctuations in the fortunes of the two ecclesiastical parties are reflected in the occupation of the patriarchal throne. The battles round the question of the union, which were waged with southern passion, were for a while checked by the dissensions aroused by the mystic tendency of the Hesychasts. The impetus to this great literary movement was given by the monk Barlaam, a native of Calabria, who came forward in Constantinople as an opponent of the Latins and was in 1339 entrusted by Andronicus III. with a mission to Pope Benedict XII. at Avignon. He condemned the doctrine of the Hesychasts, and attacked them both orally and in writing. Among those