Martyrdom of Polycarp (Latin: Martyrium Polycarpi) is a manuscript written in the form of a letter that relates the religious martyrdom of Polycarp, Bishop of Smyrna (the site of the modern city of İzmir, Turkey) in the 2nd century AD. It forms the earliest account of Christian martyrdom outside of the New Testament. The author of Martyrdom of Polycarp is unknown, but it has been attributed to members of the group of early Christian theologians known as the Church Fathers. The letter, sent from the church in Smyrna to another church in Asia Minor at Philomelium, is partly written from the point of view of an eye-witness, recounting the arrest of the elderly Polycarp, the Romans' attempt to execute him by fire, and subsequent miraculous events.
The letter takes influence from both Jewish martyrdom texts in the Old Testament and the Gospels. Furthermore, the Martyrdom of Polycarp promotes an ideology of martyrdom, by delineating the proper conduct of a martyr.
