The hagiographical material asserts that he came to Cornwall from Ireland in the company of Breage and six others, but this is attested late.
A chapel at Porthleven in Sithney parish, Cornwall, dedicated to Elwen, existed from the 13th century until 1549, and in Brittany several sites and placenames are associated with possibly related figures.
[2] Elwen appears in John Leland's extracts from a lost late-medieval Life of Saint Breage included in his Itinerary.
Leland's extracts name Elwen as one of Saint Breage's seven Irish companions who join her on her mission to Cornwall, the others being Sithney, Germoe, Mavuanus (perhaps Mawnan), Crowan, Helena, and Tecla.
In modern times a Church of St Elwyn has been established at Hayle, probably inspired by the legend recorded in Leland's work that Elwen and company had landed there from Ireland.