formerly discharged by the bishop himself. The presbyters, however, were not independent officers. They were only representatives of the bishop, and the churches over which they were set were all a part of his parish, so that the Cyprianic principle, that the bishop is necessary to the very being of the Church, held good of diocesan as well as of congregational episcopacy. The bishop alone possessed the right to ordain; through him alone could be derived the requisite clerical grace; and so the clergy like the laity were completely dependent upon him.
The growth of the diocesan principle promoted the unity of the churches gathered under a common head. But unity was carried much further than this, and finally resulted in at least a nominal consolidation of all the churches of Christendom into one whole. The belief in the unity of the entire Church had existed from the beginning. Though made up of widely scattered congregations, it was thought of as one body of Christ, one people of God. This ideal unity found expression in many ways. Intercommunication between the various Christian communities was very active. Christians upon a journey were always sure of a warm welcome and hospitable entertainment from their fellow-disciples. Messengers and letters were sent freely from one church to another. Missionaries and evangelists went continually from place to place. Documents of various kinds, including gospels and apostolic epistles, circulated widely. Thus in various ways the feeling of unity found expression, and the development of widely separated parts of Christendom conformed more or less closely to a common type. It was due to agencies such as these that the scattered churches did not go each its own way and become ultimately separate and diverse institutions. But this general unity became official, and expressed itself in organization, only with the rise of the conciliar and metropolitan systems. Already before the end of the 2nd century local synods were held in Asia Minor to deal with Montanism, and in the 3rd century provincial synods became common, and by the council of Nicaea (canon 5) it was decreed that they should be held twice every year in every province. Larger synods representing the churches of a number of contiguous provinces also met frequently; for instance, in the early 4th century at Elvira, Ancyra, Neo-Caesarea and Arles, the last representing the entire Western world. Such gatherings were especially common during the great doctrinal controversies of the 4th century. In 325 the first general or ecumenical council, representing theoretically the entire Christian Church, was held at Nicaea. Other councils of the first period now recognized as ecumenical by the Church both East and West are Constantinople I. (381), Ephesus (431), Chalcedon (451), Constantinople II. (553). All these were called by the emperor, and to their decisions he gave the force of law. Thus the character of the Church as a state institution voiced itself in them. (See Council.)
The theory referred to above, that the bishops are successors of the apostles, and as such the authoritative conservators and interpreters of apostolic truth, involves of course the solidarity of the episcopate, and the assumption that all bishops are in complete harmony and bear witness to the same body of doctrine. This assumption, however, was not always sustained by the facts. Serious disagreements even on important matters developed frequently. As a result the ecumenical council came into existence especially for the purpose of settling disputed questions of doctrine, and giving to the collective episcopate the opportunity to express its voice in a final and official way. At the council of Nicaea, and at the ecumenical councils which followed, the idea of an infallible episcopate giving authoritative and permanent utterance to apostolic and therefore divine truth, found clear expression, and has been handed down as a part of the faith of the Catholic Church both East and West. The infallibility of the episcopate guarantees the infallibility of a general council in which not the laity and not the clergy in general, but the bishops as successors of the apostles, speak officially and collectively.
Another organized expression of the unity of the Church was found in the metropolitan system, or the grouping of the churches of a province under a single head, who was usually the bishop of the capital city, and was known as the metropolitan bishop. The Church thus followed in its organization the political divisions of the Empire (cf. for instance canon 12of the council of Chalcedon, which forbids more than one metropolitan see in a province; also canon 17 of the same council: “And if any city has been or shall hereafter be newly erected by imperial authority, let the arrangement of ecclesiastical parishes follow the political and municipal forms”). These metropolitan bishops were common in the East before the end of the 3rd century, and the general existence of the organization was taken for granted by the council of Nicaea (see canons 4,6,7). In the West, on the other hand, the development was much slower.
Meanwhile the tendency which gave rise to the metropolitan system resulted in the grouping together of the churches of a number of contiguous provinces under the headship of the bishop of the most important city of the district, as, for instance, Antioch, Ephesus, Alexandria, Rome, Milan, Carthage, Arles. In canon 6 of the council of Nicaea the jurisdiction of the bishops of Alexandria, Rome and Antioch over a number of provinces is recognized. At the council of Constantinople (381) the bishop of Constantinople or New Rome was ranked next after the bishop of Rome (canon 3), and at the council of Chalcedon (451) he was given authority over the churches of the political dioceses of Pontus, Asia and Thrace (canon 28). To the bishops of Rome, Constantinople, Antioch and Alexandria was added at the council of Chalcedon (session 7) the bishop of Jerusalem, the mother church of Christendom, and the bishops thus recognized as possessing supreme jurisdiction were finally known as patriarchs.
Meanwhile the Roman episcopate developed into the papacy, which claimed supremacy over the entire Christian Church, and actually exercised it increasingly in the West from the 5th century on. This development was forwarded by Augustine, who in his famous work De civitate Dei identified the Church with the kingdom of God, and claimed that it was supreme over all the nations of the earth, which make up the civitas terrena or earthly state. Augustine’s theory was ultimately accepted everywhere in the West, and thus the Church of the middle ages was regarded not only as the sole ark of salvation, but also as the ultimate authority, moral, intellectual and political. Upon this doctrine was built, not by Augustine himself but by others who came after him, the structure of the papacy, the bishop of Rome being finally recognized as the head under Christ of the civitas Dei, and so the supreme organ of divine authority on earth (see Papacy and Pope).
Historical Sources of the First Period.—These are of the same general character for Church history as for general history—on the one hand monumental, on the other hand documentary. Among the monuments are churches, catacombs, tombs and inscriptions of various kinds, few antedating the 3rd century, and none adding greatly to the knowledge gained from documentary sources (see De Rossi, Roma sotteranea, 1864 ff., and its English abridgment by Northcote and Brownlow, 1870; André Pératé, L’Archéologie chrétienne, 1892; W. Lowrie, Monuments of the Early Church, 1901, with good bibliography). The documents comprise imperial edicts, rescripts, &c., liturgies, acts of councils, decretals and letters of bishops, references in contemporary heathen writings, and above all the works of the Church Fathers. Written sources from the 1st and 2nd centuries are relatively few, comprising, in addition to some scattered allusions by outsiders, the New Testament, the Apostolic Fathers, the Greek Apologists, Clement of Alexandria, the old Catholic Fathers (Irenaeus, Tertullian and Hippolytus) and a few Gnostic fragments. For the 3rd, and especially the 4th and following centuries, the writers are much more numerous; for instance, in the East, Origen and his disciples, and later Eusebius of Caesarea, Athanasius, Apollinaris, Basil and the two Gregories, Cyril of Jerusalem, Epiphanius, Chrysostom, Ephraim the Syrian, Cyril of Alexandria, Pseudo-Dionysius; in the West, Novatian, Cyprian, Commodian, Arnobius, Lactantius, Hilary, Ambrose, Rufinus, Jerome, Augustine, Prosper, Leo the Great, Cassian, Vincent of Lerins, Faustus, Gennadius, Ennodius, Avitus, Caesarius, Fulgentius and many others.
There are many editions of the works of the Fathers in the original, the most convenient, in spite of its defects, being that of J. P. Migne (Patrologia Graeca, 166 vols., Paris, 1857 ff.; Patrologia Latina, 221 vols., 1844 ff.). Of modern critical editions, besides those containing the works of one or another individual, the best are the Berlin edition of the early Greek Fathers (Die griechischen christlichen Schriftsteller der ersten drei Jahrhunderie, 1897 ff.), and the