Saint Tecwyn is the patron saint and founder of Llandecwyn

Llandecwyn

Llandecwyn is a village on the estuary of the Afon Dwyryd in Gwynedd, Wales. It is served by Llandecwyn railway station....

 in the Welsh

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

 county of Gwynedd

Gwynedd

Gwynedd is a county in north-west Wales, named after the old Kingdom of Gwynedd. Although the second biggest in terms of geographical area, it is also one of the most sparsely populated...

.

According to Enwogion Cymru, he was the son of Ithel Hael

Ithel Hael

Ithel Hael or Ithel Hael o Lydaw was a prince of Armorica who lived in the early part of the sixth century. He was the father of Baglan, Flewyn, Gredifael, Tanwg, Twrog, Tegai, Trillo, Tecwyn and Llechid, saints who accompanied Cadvan to Britain....

, and came to Britain with Saint Cadfan

Saint Cadfan

Saint Cadfan, ; , Abbot of Tywyn and Bardsey was a Breton Saint who lived in 6th century Wales. A Breton nobleman, he was the son of Eneas Ledewig , and Gwen Teirbron, a daughter of Budic II, a King of Brittany.- Associations & Legacy :...

, in the time of Vortigern

Vortigern

Vortigern , also spelled Vortiger and Vortigen, was a 5th-century warlord in Britain, a leading ruler among the Britons. His existence is considered likely, though information about him is shrouded in legend. He is said to have invited the Saxons to settle in Kent as mercenaries to aid him in...

"who procured wise men and divines from Gaul, now called France, to renovate Christianity in this Island, in consequence of the decay and failure that had befallen the faith in Christ."