Today (26 December) in the calendar of early western saints we commemorate St Tathai (Meuthin, Tathan, Tahai, Tathaeus, Tathar, Athaeus) of Glamorgan (Wales), hermit and abbot.
From the celt-saints list archive:
‘5th century or early 6th century. Nephew of Saint Samson of Dol, this Irish saint planted himself in the land of Wales, first as a hermit, where he founded a church at Glamorganshire and bore good fruit. His monastery at Llantathan, named after him, was one of the most famous schools in Wales. From there he went to Caerwent (Gwent), where he founded another monastic school that produced the great Celtic scholar, Saint Cadoc.
‘According to his vita, Tathai was famous as a miracle-worker and as the “Father of all Gwent, he was the defender of the woodland… no one was more generous in the West for receiving guests and giving them hospitality.” Both Caerwent and Llantathan claim to be the place where he died (Benedictines, Encyclopaedia, Farmer, Montague).’
More about the Vita and sources from Baring-Gould & Fisher, Lives of the British Saints, vol. IV.
Troparion of St Tathai tone 8 (also from the celt-saints entry, no attribution)
Teacher of true piety and blessed adornment of Christ’s Church, O Father Tathai:/ as thou didst serve Wales with thy tireless endeavours, teach us, O Saint, the virtues of unshakeable stability and loyalty to the true Faith,/ that at the end Christ our God will grant great mercy to our souls.
My translation of another troparion, from the French original by Prof. Claude Lopez-Ginisty of Acathistes et offices orthodoxes:
Troparion in Tone 3 to St Tathai, abbot (+5th c)
Born in Ireland, nephew of St Samson,
You were at first a hermit in Wales;
You then founded the monastery whence came
St Cadoc, scholar of the Celtic Church.
Miracle-worker after the example of Christ your Master,
St Tathai, pray to Him that He save our souls!
Pilgrim 