were thought of as having a head in _Peter_, the bishops of Rome, who were looked on as his successors, had accorded to them a precedence over other bishops. The grandeur of Rome, the strength of the church there, its services to other churches in the empire, especially in the West, together with many other considerations additional to its alleged historic relation to Peter and to Paul, gave to the Roman See, as time went on, a growing and acknowledged pre-eminence. The custom of holding synods helped to build up the unity of the Church, and to give power and dignity to its officials. SECTS: THEOLOGY.--The Church from the beginning had to contend with opposing sects. There was a desire to amalgamate the Christian doctrine with other systems. On the _Jewish_ side, the _Ebionites_ clung to the Old Testament ritual observances, a part of them being bitterly hostile to the Apostle Paul, and another part, the _Nazareans_, not sharing this fanatical feeling, but still adhering to the Jewish ceremonies. On the other hand, the _Gnostics_ introduced a dualism, and ascribed to the _Demiurge_--a second deity, either subordinate to the supreme God, or antagonistic to him--the origination of this world and of the Old Testament religion. They made a compound of Christianity, Judaism, and heathen religion and speculation, each Gnostic sect giving to one or the other of these ingredients the preponderance in the strange and often fantastic medley. The controversy with heathenism was prosecuted with the pen. Of the numerous defenses of Christianity, now addressed to heathen rulers and now to its opponents in private stations, the most remarkable work in the first three centuries was the writing of _Origen_--who was the most eminent of the teachers of theology at _Alexandria_--in reply to _Celsus_. Origen, after scholarly labors so vast as to earn for him the title of the _Adamantine_, died in 254, in consequence of his sufferings in the Diocletian persecution. Two defenses of the Christian faith, composed about the middle of the second century by _Justin Martyr_, are specially instructive as to the state of Christian opinion and the customs of the Church. The first great center of theological activity was _Alexandria_, where philosophy was studied in a liberal spirit. In the East, the questions relative to the divinity of Jesus and the relation of the divine to the human nature, engrossed attention. In the West, it was the practical aspects of theology, the doctrine of sin and of the deliverance of the will by grace, which were chiefly discussed. The _Arian_ controversy grew out of the assertion by _Arius_, a presbyter of Alexandria, that Jesus was the first-made of all beings, the instrument of the creation of all other beings, but himself a creature. The leader of the orthodox opposition to this opinion was the famous Alexandrian archdeacon, afterwards bishop, _Athanasius_. This debate it was which led to