He was born in the same province with Saint Sampson at Eccluis-Guenwau, near Monmouth. His sister Anaumed went over to Armorica, in 409, and upon her arrival was married to Budic king of the Armorican Britons. Before she left her own country she promised saint Theliau to consecrate her first child in a particular manner to God. Our saint was educated under the holy discipline of Saint Dubritius, and soon after the year 500, made a pilgrimage to Jerusalem with his school-fellows Saint David and Saint Paternus. In their return Saint David stopped at Dole, with Sampson the elder, who had been bishop of York, but being expelled by the Saxons, fled into Armorica and was made bishop of Dole. This prelate and Saint Theliau planted a great avenue, three miles long, from Dole to Cai, which for several ages was known by their names. The people of Dole, with the bishop and King Budic, pressed our saint to accept of that bishopric; but in vain. After his return into the island, Saint Dubritius being removed from the see of Landaff to that of Caerleon, in 495, Thelian was compelled to succeed him at Landaff, of which church he has always been esteemed the principal patron. His great learning, piety, and pastoral zeal, especially in the choice and instruction of his clergy, have procured him a high reputation which no age can ever obliterate, says Leland. His authority alone decided whatever controversies arose in his time. When the yellow plague depopulated Wales, he exerted his courage and charity with an heroic intrepidity. Providence preserved his life for the sake of others, and he died about the year 580, in a happy old age, in solitude, where he had for some time prepared himself for his passage. The place where he departed to our Lord was called from him Llan deilo-vaur, that is, the church of the great Theliau: it was situated on the bank of the river Tovy in Caermarthenshire. The Landaff register names amongst the most eminent of his disciples his nephew Saint Oudoceus, who succeeded him in the see of Landaff, Saint Ismael, whom he consecrated bishop, Saint Tyfhei, martyr, who reposeth in Pennalun, etc.
- Father Alban Butler. “Saint Theliau, Bishop in England, and Confessor”. , 1866. CatholicSaints.Info. 8 February 2013. Web. 6 October 2015. <>