First transition, to 500 ce

The new missionary faith made its first major transition as it emerged from Palestine and spread throughout the Mediterranean world. The apostle Paul became the missionary to the Gentile world. With help from St. Barnabas and a local network of coworkers, many of them women, he evangelized Asia Minor and southern Greece and eventually reached Rome. Dominated politically by the Roman Empire, the new religion benefited from the stability the empire provided and the language its elite shared—common, or Koine, Greek. Alexandrian Jews had translated (250 bce) the Hebrew Bible into Koine Greek for dispersed Greek-speaking Jews. The New Testament writers also wrote in Koine Greek. In that largely literate empire early Christians used and widely distributed the Hebrew Scriptures.

Several factors brought growth to the faith. From the beginning laypeople—both men and women—conducted the largest part of mission. Congregations grew in homes used as churches. Although the house was owned by the husband, the wife was its mistress, and women throughout the empire opened their homes to newly forming churches. Most evangelization occurred in the daily routine as men and women shared their faith with others. Christianity’s monotheism, morality, assurance of eternal life with God, and ancient Scriptures attracted many to the faith.

Christians daily encountered members of other religions—gnosticism and the mystery and philosophical cults. In the 2nd and 3rd centuries external and internal pressures drove the young church to strengthen itself through creating a structured ministry, formulating beliefs in creeds, and producing a canon of Scripture. That process established critical institutions for the early Christian movement. The major thrust of the early church-mission sprang from the conviction that Christians and congregations were fulfilling a mission and ministry begun in Jesus Christ. Baptism provided induction into the vibrant company of “God’s own people” (1 Peter 2:9–10), which many in the empire gradually accepted.

Rome, however, declared Christianity an illegal religion, in part because Christians refused to engage in emperor worship, and persecutions ensued. In the persecutions so many Christians bore witness (Greek: martyria) that the word martyr quickly evolved into its current meaning. Christian faith—not least that of young women such as Saints Blandina, Cecilia, Perpetua, and Felicity—made an impact, and many who beheld that witness became Christian. In 313 when the new emperor, Constantine I, declared the persecutions ended, Christians probably constituted 10 percent of the empire’s population.

By 315 many who saw advantage in belonging to Constantine’s new faith poured into the churches. The result was striking: small congregations of convinced Christians serving God’s outreach in the world became large churches with many nominal members whose instruction and needs had to be met. As multitudes entered the churches, the need for outreach to others was much reduced, and most churches shifted from an outward thrust to an inward focus upon themselves. Mission and service became the province of priests, deacons, and, increasingly, monks.

At the same time, mission beyond the frontiers of the empire continued. Ulfilas (c. 311–c. 382), Arian bishop and apostle to the Goths, translated the Bible into their tongue. St. Martin of Tours (c. 316–397) served in Gaul, and Patrick (c. 389–c. 461) laboured in Ireland. In Malabar, South India, a church of ancient tradition, demonstrably present since the 3rd century, held the apostle St. Thomas to be its founder. St. Frumentius (died c. 380) from Tyre evangelized in Ethiopia and became the first patriarch of its church. In the 5th century Nestorians pushed into Central Asia and began a mission that eventually reached the capital of China.

In its first 500 years Christianity achieved remarkable missionary and theological acculturation. Through the first four ecumenical councils (325–451), and in the Nicene Creed (on the Trinity) and Definition of Chalcedon (on Christology), the church had stated its faith with meaning for the Greek and Latin worlds.

By the close of the period St. Jerome’s Latin translation of the Bible, the Vulgate, had appeared, and Christianity had become the official religion of the empire. The first great transition of the Christian mission—from Judaic Palestine to the Mediterranean world—had ended.