The Letter of the Churches of Lyons and Vienne is a collective document from the 2nd century CE, not the work of a single author. It was sent around 177 CE, during the reign of Emperor Marcus Aurelius, from the Christian communities in Roman Gaul (modern Lyon and Vienne, France) to fellow churches in Asia Minor. The letter provides a detailed eyewitness account of a severe local persecution.

It describes mob violence, imprisonment, and public executions in the arena, naming specific martyrs like the elderly bishop Pothinus, the slave Blandina, and a youth named Ponticus. The community included both local members and immigrants, showing the spread of Christianity into the western Roman provinces. The original Greek text is lost but is preserved because it was quoted extensively by the historian Eusebius of Caesarea in the 4th century.

According to modern scholars, the letter is a foundational source for understanding early Christianity outside the Mediterranean core. It reveals the social dynamics of persecution and the early theology of martyrdom, portraying death for the faith as a spiritual victory. The document also shows the early church’s internal concerns, such as caring for those imprisoned and debating how to treat members who renounced their faith under pressure. Its preservation by Eusebius made it highly influential for later Christian historiography and the veneration of saints.