before them. The laws against them were renewed by Leo the Armenian (813-820); but the empress Theodora caused the acts of the Council of Nicæa to be reaffirmed (842). The conflict, which had lasted more than a hundred years, ended in the complete triumph of the images, and the Festival of Orthodoxy, observed to this day in the Greek Church, was instituted to commemorate it.

Throughout this struggle the Roman Church arrayed itself against the "image-breakers" and anathematised their doctrine. The council of 754 was not recognised in the West; legates of Pope Adrian I were present at Irene's council in 787, where a dogmatic pronouncement in favour of imageworship was made. The Frankish church in those days had a mind and voice of its own. It would neither exclude images from the churches nor approve the veneration of them. When the acts of the Nicene Council of 787 were transmitted by Pope Adrian to Charles the Great, the answer, made in the king's own name, maintained this position, unshaken by the conjoint authority of an œcumenical council and the pope. The new council, he affirmed, was as bad as its predecessor; pictures are properly allowed in churches as representations of events or for the decoration of the walls, but adoration of them should be strictly forbidden. A synod at Paris in 825 accompanied its condemnation of image-worship with an express censure of Pope Adrian for lending his authority to the superstitious practices prevailing in Italy and at Rome, which he ought to have resisted. Through the greater part of the ninth century the worship of images continued to be forbidden in the Frankish kingdoms; but in the end it prevailed there also.

The belief that sins committed after baptism must be expiated by suffering, which is the basis of the penitential discipline of the church, received an extension or complement in the Western church in the doctrine of purgatory.1 Christians who die with minor sins unatoned for undergo for a longer or shorter time a purification by fire, and only

1 The Greek and Oriental churches have no corresponding doctrine.

after their release from this place of suffering are admitted to the abode of the blessed. Gregory the Great, who did much to give currency and authority to this belief, taught, as we have seen, that the sacrifice of the Mass avails to atone for the sins of the dead as well as the living, and thus to abridge the time of purgatorial torment or secure release from it, and this is the doctrine of the Western church.

The six or seven centuries with which we have hitherto been engaged are the formative period of the Christian religion. By the end of this period-and for the most part long before-its distinctive doctrines had been authoritatively defined and generally accepted in the terms of the creeds; it had also in the writings of the Fathers a classical theological literature of hardly inferior authority; its organisation, institutions, and forms of worship were fully established; it had developed its own types of asceticism and of mysticism. Certain great questions had not been formally decided the problems of grace and freedom, in the West, for example; others, like the work of Christ, in distinction from his person, had not been adequately discussed, far less satisfactorily solved. But however much was thus left for future generations to do, the decisions of the great councils, the consensus of the Fathers, the prescription of custom, the body of tradition, were regarded on all hands as the unalterable norm of the Christian religion; such it had always been, and such it should always be. That this was an illusion, both as to the past and the future, may seem to the historian palpable; but it was a conservative force of immeasurable consequence. And this Catholic Christianity, whose origins lie in the Apostolic or sub-Apostolic Age, which appears fully developed before the end of the ancient age and was perpetuated essentially unchanged through the Middle Ages, remains to the present day the religion of by far the greater part of Christendom.

CHAPTER IX

CHRISTIANITY

THE MIDDLE AGES

Moslem Conquests-Final Breach between the Eastern and Western Churches-Teutonic Invasions-Conversion of the Germanic Peoples-Carolingian Revival of Learning Eucharistic Controversies-The Medieval Penitential Discipline-IndulgencesTreasury of Merit-Anselm's Cur Deus Homo-Church and State: Augustine's Civitas Dei-The Frankish and German Emperors— The Conflict over Investitures-The Issue of Supremacy: Gregory VII, Innocent III, Boniface VIII-Denials of Papal ClaimsThe Great Councils: Pisa, Constance, Basel, Florence-Restoration of Papal Power.

THE Moslem conquests of the seventh century in the space of a few years wrested Syria and Egypt from the empire, while Asia Minor was subjected to ever-renewed invasions which more than once brought the crescent within sight of Constantinople. The conquerors did not discriminate among the theological varieties of their Christian subjects; to the churches which had been under the disabilities of heresy in the empire the impartial toleration of the caliphate was a deliverance. The great church, on the other hand, lost the privileges it had enjoyed as the state church of the empire and the material advantages that accrued from this position. All branches of the church were confronted by the urgent practical task of adjusting themselves to the new situation and of maintaining their hold on the Christian population, resisting the strong motives to defection which the legal and social inferiority of Christians and the incidence of taxation presented. It might have been thought that under these circumstances they would have been drawn together into some kind of union, but this was not the case; doctrinal differences had long since been organised in rival churches which had no communion with

one another, and as the heretical churches had their strongholds among certain populations Copts, Armenians, Syrians-language was another and permanent divisive principle.

The intellectual life of the Eastern churches was not extinguished by the advent of Islam. A century after the conquest the Greek church had its first and last-great systematic theologian in John of Damascus, the son of an official of high rank in the service of the caliph, and himself brought up to the same service. His work became the classic of orthodoxy. But the age was past when Greek theologians took the leading part in the discussion and definition of Christian doctrine. The history of theology in the Greek and Oriental churches is in itself an interesting and too much neglected subject; but it may without injustice be said that since the eighth century those churches have had no appreciable part in the historical development of Christianity as a whole.

Notwithstanding sharp conflicts which more than once temporarily interrupted the communion of the Roman Church with the East, the idea of the unity of the church universal was too firmly established and the actual bond of union too strong to permit non-intercourse to harden into permanent division. But in time the complete separation of the Latin-German West from the Byzantine empire dissolved the political ties; the attempts of the popes to assert their headship of the whole church by intervention in internal affairs of the patriarchate of Constantinople; the conservative orthodoxy of the Greeks, who regarded the more progressive West with suspicion and magnified into heresy all departures from their own formulas and customs, led in 1054 to the final breach, when the Pope's legates laid on the altar of Santa Sophia a bull of excommunication against the Patriarch, to which he at once replied in kind by launching an anathema against the Pope. The Oriental patriarchs naturally sided with their Constantinopolitan colleague against the pretensions of Rome. The severance of the

East and the West was complete, and repeated efforts to reunite them came to naught. Through causes partly theological and ecclesiastical, partly political, the gulf has but widened in the course of the centuries.

The great migrations and their political results brought within the sphere of the Greek church and its missionary activity chiefly Slavic (or Slavonised) peoples, and the national churches of Russia, Servia, and Bulgaria, which are sprung from it, contain the great bulk of its present adherents. The racial characteristics of these peoples and their civilisation have made their impress on their Christianity in manifold ways, while the original Greek element has become relatively inconsiderable.

Of the Oriental churches especial interest attaches to that which is commonly called Nestorian, in which the position of the so-called Oriental party in the controversy over the divine and human natures in Christ was perpetuated. Driven from Edessa, where they had maintained a flourishing school, they sought in Persia the toleration that was denied them in the Christian empire, and established at Nisibis a seminary of biblical and theological learning in which the best traditions of the Antiochian school were perpetuated. In the face of repeated and severe persecutions by Persian kings set on by the Zoroastrian clergy, they displayed much zeal for the conversion of the people; in the following century their missions carried Christianity through central Asia, and by 635 they had reached China. In their efforts to convert the Mongols they found themselves in competition with Buddhist monks, and ere long Islam also entered the field. In our own day a remnant of this once numerous and enterprising church survives on the shores of Lake Urmia and in the neighbouring mountains of Kurdistan, and American (Presbyterian), English (Church of England), Roman Catholic, and Russian Orthodox missionaries have vied with one another to convert this handful of Syrian Christians to some one or other of these varieties of alien Christianity, or from one of them to another.