Describing Caerleon, which he visited early in the 13th Century, Giraldus Cambrensis says: “lulius and Aaron, after ‘suffering martyrdom, were buried in this city and each had a church dedicated to him. After Alban and Amphibalus they were esteemed the chief proto-niartyrsof Britannia Major. In ancient times there were three fine churches in this city, one dedicated to 1 ulius the martyr, graced’ with a ~hoir of nuns, another to Aar on, his associate, and enobled with an order of canons, and -the third distinguished as the metropolitan see of Wales. Amphibalus was born in this place .•..• and here also Archbishop Dubr ic ius ceded his honours to David of Menev ia, the metropolitan see being translated from this place to Menevia, according to the prophecy of Merlin Ambrosius – “Menevia shall be invested with the pall of the City of Legions.”

The metropolitan see remained at Caerleon until the end of the episcopate of Dyfrig, Archbishop of Caerleon and Bishop of Llandaff who in 519 resigned in favour of David (the Welsh patron saint). David moved the see to his home town Menevia and founded there St David’s Cathedral. The bishops of St David’s continued to act as metropolitans for the whole of Wales until, in 1115, Bernard, Bishop of St David’s, a Norman appointed by Henry I, professed subjection to the see of Canterbury. In 600 at a conference with Augustine, the Welsh bishops had refused to recognise the authority of Rome and in 664, at the Synod of Whitby, the Welsh Church was declared schismatic. By the end of the eighth century, however, it had become part of the Church of Rome and towards the close of the twelfth centry, it was merged into the Church in England. In this district, union with England took place earlier than in the rest of Wales, for Urban, Bishop of Llandaff, submitted to the authority of Canterbury in 1107. In 1284 Peckham, Archbishop of Canterbury, paid his first official Visitation to the Welsh Church and in July of that year he stayed in Newport. Haddan and Stubbs (Ecclesiastical Councils and Documents, 1869) quote a letter to Edward I reporting on the situation in Wales, which Peckham wrote from Newport.