According to tradition, Christianity arrived in Britain in the 1st or 2nd century, during which time southern Britain became part of the Roman Empire. The earliest historical evidence of Christianity among the native Britons is found in the writings of such early Christian Fathers as Tertullian and Origen in the first years of the 3rd century. Three Romano-British bishops, including Restitutus, are known to have been present at the Council of Arles in 314. Others attended the Council of Serdica in 347 and that of Ariminum in 360, and a number of references to the church in Roman Britain are found in the writings of 4th century Christian fathers. Britain was the home of Pelagius, who opposed Augustine of Hippo's doctrine of original sin.