Dictionary of Welsh Biography

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TYSILIO , a 7th cent. Celtic saint ,

said to be the son of Brocmail , prince of Powys . No ‘Life’ of S. Tysilio survives in Wales but he is given a genealogy in ‘ Bonedd y Saint ’ and there is a poem in his honour written by Cynddelw in the second half of the 12th cent. He is mentioned again in the ‘Life’ of S. Beuno written by an anchorite of Llanddewi-brefi in 1346 . It would appear that his legend was borrowed in the 15th cent. by the monks of S. Suliac in Brittany or by some canons of S. Malo , interested in Suliac in order to write up a legendary of the patron of that church the details of whose life had long since been forgotten. In this way S. Tysilio became identified with S. Suliac and the Welsh saint's legend is preserved for us in the ‘Life’ of the patron of S. Suliac . From his ‘Life’ we learn hat S. Tysilio wished as a lad to embrace the religious life and left his family and went to Meifod in Montgomeryshire to be instructed by the abbot Gwyddfarch . Later he retired to the shore of the Menai and founded there the church of Llandysilio . After his return to Meifod he was subjected to considerable annoyance at the hands of his sister-in-law and consequently fled to Brittany and founded the church of S. Suliac on the estuary of the Rance . The topographical evidence of the cult of S. Tysilio is for the most part a reflection of this legend or quite possibly, the legend might be an attempt to explain the distribution of the ancient churches bearing his name. He is clearly a Powysian saint with outlying dedications on the Menai , near the south Cardiganshire coast, and close to the present Pembrokeshire - Carmarthenshire border. The location of these outlying dedications strongly suggests that S. Tysilio did on some occasion journey along the much frequented western sea-routes so beloved by many another Celtic saint . As we have seen there is no evidence at all that he himself crossed the Channel to Brittany , but it is certain that his legend did so in later times.


  • The Lives of the British Saints , iv, 296-305;
  • Wade-Evans , Welsh Christian Origins (Oxford, 1934) , ‘ 1934 , 167;
  • G. H. Doble , Saint Sulian and Saint Tysilio (Guildford, 1936) , Cornish Saint Series No. 37, 1936 ;
  • E. G. Bowen , ‘The Saints of Gwynedd,’in Caernarvonshire Historical Society Transactions . 1948 , 13-5.


Professor Emrys George Bowen, M.A., F.S.A., (1900-83), Aberystwyth

Published date: 1959