The Church and the state at the end of the fourth century
Theodosius the Great and the triumph of Christianity. During the reign of Julian's successor, Jovian (363-64), a devoted follower of the Nicene Creed, Christianity was restored to its former position. This did not involve new persecutions of the pagans, however, whose fears on this account at the time of Jovian's succession proved to be unfounded. Jovian intended to establish throughout the empire the order which had existed before Julian. He proclaimed complete religious toleration. He allowed the pagans to reopen their temples and continue the offering of sacrifices. In spite of his adherence to the Nicene doctrines, he undertook no compulsory legislation against the other ecclesiastical parties. Christian exiles of different sects returned from banishment. The labarum appeared again in the army. Jovian reigned only a few months, but his activity in the realm of ecclesiastical affairs made a strong impression on his contemporaries. The Christian historian of the fifth century, Philostorgius, an Arian, remarked: The Emperor Jovian restored the churches to their original uses, and set them free from all the vexatious persecutions inflicted on them, by the Apostate.
Jovian died suddenly in February, 364. He was succeeded by two brothers, Valentinian I (364-75) and Valens (364-78), who divided the rule of the Empire: Valentinian became the ruler of the western half of the Empire and Valens was authorized to govern the eastern half. The brothers differed greatly in their religious outlook. Valentinian followed the Nicene Creed; Valens was an Arian. But the Nicene allegiance of Valentinian did not make him intolerant of other creeds, and during his reign religious freedom was more secure and complete than before. At the beginning of his rule he issued a decree granting each man the freedom of worshiping whatever his conscience dictated to him. Paganism was freely tolerated. Yet Valentinian showed that he was a Christian emperor by a number of measures; one of them restored all the privileges granted the clergy by Constantine the Great. Valens followed an entirely different policy. Upon declaring himself a follower of Arianism, he became intolerant of all other Christian doctrines, and though his persecutions were neither severe nor systematic, people in the eastern part of the Empire did go through a period of great fear and anxiety during his reign.