Olyroun
Oléron is an island off the coast of Britain in Chestre’s Launfal.
The King of Oléron’s daughter, Triamour, became the lover of Sir Launfal (Lanval). She and Launfal eventually went to Oléron, where they remained.
Counterparts in other tales are Avalon and Amylion.
Source
Sir Launfal | Thomas Chestre, late 14th century