Christianity in the Roman Empire

Christianity developed in Judea in the mid-first century CE, based first on the teachings of Jesus and later on the writings and missionary work of Paul of Tarsus.

Originally, Christianity was a small, unorganized sect that promised personal salvation after death. Salvation was possible through belief in Jesus as the son of God—the same God the Jews believed in. Early Christians debated whether they should only preach to Jews, or if non-Jews could become Christians, too. Eventually, Christianity gained followers not only from Jewish communities, but from throughout the Roman world.

In the decades after Jesus's death, the Apostle Paul wrote many letters that are now part of the New Testament of the Christian Bible. Paul was a Roman citizen and sent these letters to small communities of Christians living throughout the Roman Empire. The letters show us that Paul and his fellow Christians were still figuring out exactly what being a Christian meant. Issues related to the exact relationship between Judaism and Christianity, and between Christianity and the Roman government, were prominent topics of discussion.

Judaism had received the status of a legal religion in the Roman Empire with formal protections. Although Christianity developed out of Jewish traditions, it had no such legal protections. Christians were occasionally persecuted—formally punished—for their beliefs during the first two centuries CE. But the Roman state’s official position was generally to ignore Christians unless they clearly challenged imperial authority.

In 313 CE, the emperor Constantine issued the Edict of Milan, which granted Christianity—as well as most other religions—legal status. While this was an important development in the history of Christianity, it was not a total replacement of traditional Roman beliefs with Christianity.

In 325, Constantine called the Council of Nicaea, which was a gathering of Christian leaders to determine the formal—or orthodox—beliefs of Christianity. The result of this council was the Nicene Creed, which laid out the agreed upon beliefs of the council.

In 380 CE, the emperor Theodosius issued the Edict of Thessalonica, which made Christianity, specifically Nicene Christianity, the official religion of the Roman Empire. Most other Christian sects were deemed heretical, lost their legal status, and had their properties confiscated by the Roman state.

The Roman Empire did not become Christianized overnight. Roman religious beliefs changed slowly over time. At the time the Western Roman Empire fell in 476 CE, Christianity was still spreading. It is also important to remember that Christianity itself did not appear suddenly or fully-formed. Christianity grew out of Jewish traditions and was shaped by Roman cultural and political structures for several centuries.

To take one lasting example, the head of the Roman Catholic Church—the Pope—takes his title from the old Roman office of pontifex maximus—the high priest. Roman culture was not wholly replaced, but was often repurposed as it came into contact with other peoples and cultures.

Christianity was deeply influenced by both Judaism and Roman cultural institutions. We can't fully understand the development of the Christian religion without putting it into these contexts!