The Councils.—In this century began the councils, the great assemblies of the church. There had already been some local councils at which the bishops and priests of a single province had been present. For the first time, in 324,[175] Constantine convoked a General Assembly of the World (an ecumenical council) at Nicæa, in Asia Minor; 318 ecclesiastics were in attendance. They discussed questions of theology and drew up the Nicene Creed, the Catholic confession of faith. Then the emperor wrote to all the churches, bidding them "conform to the will of God as expressed by the council." This was the first ecumenical council, and there were three others[176] of these before the arrival of the barbarians made an assembly of the whole church impossible. The decisions reached by these councils had the force of law for all Christians: the decisions are called Canons[177] (rules). The collection of these regulations constitutes the Canon Law.
The Heretics.—From the second century there were among the Christians heretics who professed opinions contrary to those of the majority of the church. Often the bishops of a country assembled to pronounce the new teaching as false, to compel the author to abjure, and, if he refused, to separate him from the communion of Christians. But frequently the author of the heresy had partisans convinced of the truth of his teaching who would not submit and continued to profess the condemned opinions. This was the cause of hatred and violent strife between them and the faithful who were attached to the creed of the church (the orthodox). As long as the Christians were weak and persecuted by the state, they fought among themselves only with words and with books; but when all society was Christian, the contests against the heretics turned into persecutions, and sometimes into civil wars.
Almost all of the heresies of this time arose among the Greeks of Asia or Egypt, peoples who were subtle, sophistical, and disputatious. The heresies were usually attempts to explain the mysteries of the Trinity and of the Incarnation. The most significant of these heresies was that of Arius; he taught that Christ was created by God the Father and was not equal to him. The Council of Nicæa condemned this view, but his doctrine, called Arianism, spread throughout the East. From that time for two centuries Catholics and Arians fought to see who should have the supremacy in the church; the stronger party anathematized, exiled, imprisoned, and sometimes killed the chiefs of the opposition. For a long time the Arians had the advantage; several emperors took sides with them; then, too, as the barbarians entered the empire, they were converted to Arianism and received Arian bishops. More than two centuries had passed before the Catholics had overcome this heresy.
Paganism.—The ancient religion of the Gentiles did not disappear at a single stroke. The Orient was quickly converted; but in the Occident there were few Christians outside the cities, and even there many continued to worship idols. The first Christian emperors did not wish to break with the ancient imperial religion; they simultaneously protected the bishops of the Christians and the priests of the gods; they presided over councils and yet remained pontifex maximus. One of them, Julian (surnamed the Apostate), openly returned to the ancient religion. The emperor Gratian in 384[178] was the first to refuse the insignia of the pontifex maximus. But as intolerance was general in this century, as soon as the Roman religion ceased to be official, men began to persecute it. The sacred fire of Rome that had burned for eleven centuries was extinguished, the Vestals were removed, the Olympian games were celebrated for the last time in 394. Then the monks of Egypt issued from their deserts to destroy the altars of the false gods and to establish relics in the temples of Anubis and Serapis. Marcellus, a bishop of Syria, at the head of a band of soldiers and gladiators sacked the temple of Jupiter at Aparnæa and set himself to scour the country for the destruction of the sanctuaries; he was killed by the peasants and raised by the church to the honor of a saint.
Soon idolatry persisted only in the rural districts where it escaped detection; the idolaters were peasants who continued to adore sacred trees and fountains and to assemble in proscribed sanctuaries.[179] The Christians commenced to call "pagans" (the peasants) those whom up to this time they had called Gentiles. And this name has still clung to them. Paganism thus led an obscure existence in Italy, in Gaul, and in Spain down to the end of the sixth century.
Theodosius.—The incursions of the Germanic peoples into the empire continued for two centuries until the Huns, a people of Tartar horsemen, came from the steppes of Asia, and threw themselves on the Germans, who occupied the country to the north of the Danube. In that country there was already a great German kingdom, that of the Goths, who had been converted to Christianity by Ulfilas, an Arian. To escape the Huns, a part of this people, the West Goths (Visigoths), fled into Roman territory, defeated the Roman armies, and overspread the country even to Greece. Valens, the emperor of the East, had perished in the defeat of Adrianople (378); Gratian, the emperor of the West, took as colleague a noble Spaniard, Theodosius by name, and gave him the title of Augustus of the East (379). Theodosius was able to rehabilitate his army by avoiding a great battle with the Visigoths and by making a war of skirmishes against them; this decided them to conclude a treaty. They accepted service under the empire, land was given them in the country to the south of the Danube, and they were charged with preventing the enemies of the empire from crossing the river.
Theodosius, having reëstablished peace in the East, came to the West where Gratian had been killed by order of the usurper Maximus (383). This Maximus was the commander of the Roman army of Britain; he had crossed into Gaul with his army, abandoning the Roman provinces of Britain to the ravages of the highland Scotch, had defeated Gratian, and invaded Italy. He was master of the West, Theodosius of the East. The contest between them was not only one between persons; it was a battle between two religions: Theodosius was Catholic and had assembled a council at Constantinople to condemn the heresy of Arius (381); Maximus was ill-disposed toward the church. The engagement occurred on the banks of the Save; Maximus was defeated, taken, and executed.
Theodosius established Valentinian II, the son of Gratian, in the West and then returned to the East. But Arbogast, a barbarian Frank, the general of the troops of Valentinian, had the latter killed, and without venturing to proclaim himself emperor since he was not a Roman, had his Roman secretary Eugenius made emperor. This was a religious war: Arbogast had taken the side of the pagans; Theodosius, the victor, had Eugenius executed and himself remained the sole emperor. His victory was that of the Catholic church.
In 391 the emperor Theodosius promulgated the Edict of Milan. It prohibited the practice of the ancient religion; whoever offered a sacrifice, adored an idol, or entered a temple should be condemned to death as a state criminal, and his goods should be confiscated to the profit of the informer. All the pagan temples were razed to the ground or converted into Christian churches. And so Theodosius was extolled by ecclesiastical writers as the model for emperors.
Theodosius gave a rare example of submission to the church. The inhabitants of Thessalonica had risen in riot, had killed their governor, and overthrown the statues of the emperor. Theodosius in irritation ordered the people to be massacred; 7,000 persons suffered death. When the emperor presented himself some time after to enter the cathedral of Milan, Ambrose, the bishop, charged him with his crime before all the people, and declared that he could not give entrance to the church to a man defiled with so many murders. Theodosius confessed his sin, accepted the public penance which the bishop imposed upon him, and for eight months remained at the door of the church.