The Black Book of Carmarthen
The connection between St Peter's and Carmarthen Priory begins when the Augustinian Priory was first founded sometime between 1120 and 1125. But the connection might be a lot earlier and linked to Llandeulyddog, a Bishop House and early cult centre of St Teilo, a cousin and disciple of St David, which may have been founded in the 6th century. An associated monastic enclosure existed by the 8th century and it is thought that St Peter's is the sole survivor of a number of churches which once existed in this enclosure.