Of Irish origin, Tathai became a hermit in Wales and later founded the monastery of Llantathan (St Athan). From here he came to Caerwent (Gwent), where he founded a monastic school. If we are to believe the Life, he was famous in the neighbourhood as a miracle-worker and as the ‘Father of all Gwent, he was the defender of the woodland country…he was never angry…whatever was given to him, he gave to others…no-one was more generous in the West for receiving guests and giving them hospitality.’ He probably died at Caerwent, but Llantathan also claimed to be his death-place. Feast: 26 December.
N.L.A., ii. 361–3; A. W. Wade-Evans, Vitae Sanctorum Britanniae (1944), 270–87; Baring-Gould and Fisher, iv. 211–14.