St Euny was an early Christian preacher, who arrived in Cornwall to promote Christianity before it became the main religion there. He travelled with his brother Erc and sister Ia from Ireland, and all three of these saints later founded Cornish churches and communities. St Erc founded St Erth, St Ia founded St Ives and St Euny founded the churches at Lelant and Redruth.
There are also a number of holy wells dedicated to St Euny in West Cornwall. Like many Cornish feast days, St Euny Feast was once a major event with families holding special meals. Today, it is celebrated in Lelant with a church service followed by a feast dinner.