Salomon (also known, in Welsh, as Selyf) was a late 5th century Cornish 'warrior prince', possibly a King of Cornwall.
St Levan (properly Selevan, a Celtic form of Solomon) according to the Life of St Kybi was a Cornishman and the father of Kybi. In the department of Morbihan are four places probably connected to the same saint, who probably lived in the 6th or 7th century. On the cliff at St Levan is St Levan's Well and below it the probable remains of his chapel, which were described by William Borlase in his Antiquities. Salomon is recorded, in the 'Life of Saint Cybi' as a princeps militiae living in Eastern Cornwall, where Cybi, his son, was born. Wade-Evans interpreted his title as 'captain of the guard', while others believe he was a sub-king of Cornwall. David Nash Ford suggests that he succeeded to the realm of his cousin, King Mark.
Cybi's 'life' gives Salomon's father as Erbin ap Geraint ap Lud, but the Welsh Bonedd y Saint states his father was Geraint ab Erbin ap Custennin Gorneu. Erbin and Geraint have evidently been switched around, but it is unclear which position is correct. Geraint ab Erbin is certainly a character in the Welsh Arthurian story of Culhwch and Olwen. Custennin is known from other records, but Lud is not and may be a further mistake. Salomon married Gwen, the daughter of an Irish prince who had settled at Caer-Goch near St David's in Pembrokeshire.
Salomon is sometimes identified with one or both known Saints Selevan, of St Levan in Cornwall and Penmon on Anglesey, or with Salwys, the supposed founder the church of Lansallos, also in Cornwall.