About 56 BC, during the Roman invasion of Gaul, the area was occupied by refugees from Armorica. In Britanny, there was a small population in two villages residing in crannogs (artificial islands.) Some of their wares were exported to Britain and Ireland. Glastonbury, from ancient times had been an active seaport on the Severn estuary and situated to be the entrance point for a new religion into western Britain. With western Armorica having already evolved into Brittany, when Vikings or Northmen settled in the Cotentin peninsula and the lower Seine around Rouen in the 9th and early 10th centuries, and these regions came to be known as Normandy, the name Armorica fell out of use. Bede supplies no names of British Christians prior to the era of Diocletian (284-305), whose reign he places the martyrdom of St. Alban of Verulam. The district around Verulam had been occupied by Belgae before Caesar's time. The pagan Britons had worshiped not in temples but in groves. After Constantine's edict of liberation (313), churches arose bearing resemblance to the shrines of Mithra and other pagan Roman temples. The most complete in Roman times, being that of Silchester in Hampshire; the Roman Calleva.
The church among the Roman Britons took its place with the continental churches through the attendance of British bishops and other clergy in various fourth centry synods. When the Donatist schism arose in North Africa and threatened to disrupt the church in the western provinces, Constantine the Great called a council at Arles to settle the controversy in 314. In addition to the bishops of North Africa, bishops and other clergy representing thirty-five sees in Gaul, Britian, Spain, Italy, and Dalmatia were present. The council adopted a series of twenty-two firmly phrased disciplinary canons. The signatories include three bishops from Britain- Eborius of York, Restitutus of London, and Adelphius, whose see may have been either Lincoln or Caerleon-upon-Usk, or Colchester. A presbyter named Sacerdos and a deacon named Arminius were also in the deputation from Britian. The bishops of Gaul numbered thirty-six and of sixteen were present at the synod. Only one yeare had passed since the Edict of Milan where the epsicopate must have come into existence in Britain, as in Gaul, at an earlier period than Constantine. The robed clergymen who appears in the Alban incident is not new then. The pioneer bishops may have been designated and consecrated in Gaul or in Rome. The names of those at Arles are in Latin form, furthermore, from the southeastern region, although early episcopal consecrations in or for Britain sees are unknown. The intimate relations of the British church with that of Gaul and with the diocese of Auxerre, in the fifth century, may have anticipated a fourth.
An early Welsh story links Arthur to the Tor in an account of a face-off between Arthur and the Celtic king, Melwas, who had apparently kidnapped Arthur's wife Queen Guinevere. Geoffrey of Monmouth first identified Glastonbury with Avalon in 1133. In 1191, monks at the Abbey claimed to have found the graves of Arthur and Guinevere to the south of the Lady Chapel of the Abbey church, which was visited by a number of contemporary historians including Giraldus Cambrensis. The remains were later moved, and lost during the Reformation. Glastonbury today is a centre for religious tourism and pilgrimage. King Arthur and Guinevere were supposedly buried at Glastonbury Abbey. Other points of interest include St. John's Church and the Chalice Well.