In the Roman Empire polytheism was practiced, and religions indigenous to particular Middle Eastern nations became international in the first 3 centuries of the Roman Empire. Roman citizens worshiped Isis of Egypt, Mithras of Persia, Demeter of Greece, and the great mother Cybele of Phrygia. Their cults centered on mysteries (secret ceremonies) and the promise of an afterlife, symbolized by the death and rebirth of the god. The Jews living in the empire preserved their monotheistic religion- Judaism, the world’s oldest (c 1200 bc) continuous religion. Its teachings are contained in the Bible (the Old Testament). First-century Judaism embraced several sects, including the Sadducees, mostly drawn from the Temple priesthood, who were culturally Hellenized; the Pharisees, who upheld the full range of traditional customs and practices as of equal weight to literal scriptural law and elaborated synagogue worship; and the Essenes, an ascetic, millennarian sect. Messianic fervor led to repeated, unsuccessful rebellions against Rome (66-70, 135). As a result, the Temple in Jerusalem was destroyed and the population decimated; this event marked the beginning of the Diaspora (living in exile).
To avoid the dissolution of the faith, a program of codification of law was begun at the academy of Yavneh. The work continued for some 500 years in Palestine and in Babylonia, ending in the final redaction (c 600) of the Talmud, a huge collection of legal and moral debates, rulings, liturgy, biblical exegesis, and legendary materials.
Christianity, which emerged as a distinct sect in the second half of the 1st cent. ad, is based on the teachings of Jesus, whom believers considered the Savior (Messiah or Christ) and the son of God. The missionary activities of the Apostles and such early leaders as Paul of Tarsus spread the faith. Intermittent persecution, as in Rome under Nero in 64 ad, on grounds of suspected disloyalty, failed to disrupt the Christian communities. Each congregation, generally urban and of plebeian character, was tightly organized under a leader (bishop), elders (presbyters or priests), and assistants (deacons). The four Gospels (accounts of the life and teachings of Jesus) and the Acts of the Apostles were written down in the late 1st and early 2d centuries and circulated along with letters of Paul and other Christian leaders. An authoritative canon of these writings was not fixed until the 4th century.
A school for priests was established at Alexandria in the 2d century. Its teachers (Origen c 182-251) helped define Christian doctrine and promote the faith in Greek-style philosophical works. Pagan Neoplatonism was given Christian coloration in the works of Church Fathers such as Augustine (354-430). Christian hermits, often drawn from the lower classes, began to associate in monasteries, first in Egypt (St. Pachomius c 290-345), then in other E lands, then in the W (St. Benedict’s rule, 529). Popular devotion to saints, especially Mary, mother of Jesus, spread.
Under Constantine (r 306-37), Christianity became in effect the established religion of the Empire. Pagan temples were expropriated, state funds were used to build huge churches and support the hierarchy, and laws were adjusted in accordance with Christian ideas. Pagan worship was banned by the end of the 4th century, and severe restrictions were placed on Judaism.
The newly established church was rocked by doctrinal disputes, often exacerbated by regional rivalries both within and outside the Empire. Chief heresies (as defined by church councils backed by imperial authority) were Arianism, which denied the divinity of Jesus; the Monophysite position denying the dual nature of Christ; Donatism, which denied the validity of sacraments performed by sinful clergy; and Pelagianism, which denied the necessity of unmerited grace for salvation.