The Rise of Christianity in the Roman Empire

Core Idea

Christianity began as a movement among Jews in Roman Judea who followed Jesus of Nazareth, executed by crucifixion under the Roman governor Pontius Pilate around 30 CE. Within three centuries it spread across the Mediterranean world, carried along Roman roads and sea lanes, through Greek-speaking cities and Jewish communities. Christians faced local hostility and, at times, empire-wide persecution. The emperor Constantine's support after 312 CE changed its position, and under Theodosius I in 380 CE Nicene Christianity became the official religion of the empire.

How It's Best Learned

Build a timeline from Jesus to Theodosius and mark when Christians were tolerated, persecuted or favored. Read short primary sources, such as a letter of Paul and the exchange between Pliny the Younger and the emperor Trajan about Christians. Ask why a small, unlicensed group worried Roman officials and why it still grew. Connect the spread to Roman infrastructure and the common Greek language of the eastern empire.

Common Misconceptions

• Constantine made Christianity the official religion of the Roman Empire. (The Edict of Milan in 313 granted toleration to Christians and all other religions; Nicene Christianity became the official state religion under Theodosius I in 380.)
• Rome persecuted Christians constantly for three hundred years. (Most persecution before 250 was local and sporadic; the empire-wide persecutions came under Decius, Valerian and, most severely, Diocletian from 303.)
• Early Christianity was a single, uniform church from the start. (Early communities differed in practice and belief, and councils such as Nicaea in 325 were called to settle disputes over doctrine.)

Explainer

Rome ruled a very mixed empire, and it usually let its peoples keep their own gods. It expected one thing in return: respect for the gods of the state and, from the time of Augustus, honor for the emperor. Most groups could do this without trouble. The early Christians could not, and this tension shaped their first three centuries.

Jesus of Nazareth was a Jewish teacher in Galilee and Judea. Around 30 CE the Roman governor Pontius Pilate had him crucified. His followers proclaimed that he had risen from the dead and was the Messiah. Within a generation, Paul of Tarsus and other missionaries carried this message to cities in Syria, Asia Minor, Greece and Rome. Paul's letters, written in the 50s CE, are the oldest surviving Christian texts. They show small groups meeting in homes and arguing over whether non-Jewish converts had to follow Jewish law.

Several features of the Roman world helped the new faith spread. Roads and sea routes were relatively safe. Greek was widely spoken in the east. Large cities held many people looking for community and meaning, as the popularity of mystery religions also shows. Christian groups offered care for widows, the sick and the poor, which drew attention.

Roman responses changed over time. In 64 CE, Nero blamed Christians for the great fire in Rome, according to the historian Tacitus. For the next two centuries, Christians were punished mainly when local people accused them. In 250, the emperor Decius ordered all inhabitants to sacrifice to the gods, and those who refused could be executed. The most severe effort, the Great Persecution, began under Diocletian in 303.

The turning point was Constantine. Before the Battle of the Milvian Bridge in 312 he adopted a Christian sign, and after his victory he favored the church. The Edict of Milan in 313 granted toleration. In 325 Constantine called the Council of Nicaea to settle a dispute about the nature of Christ. In 380 Theodosius I declared Nicene Christianity the official religion, and in the 390s he banned pagan sacrifice. A persecuted minority had become the faith of the state.