Elaeth (sometimes recorded as Eleth) was a Christian king and poet in Britain in the 6th century who is venerated as a saint. After losing his territory in the north of Britain, he retreated to Anglesey, north Wales, where he lived at a monastery run by St Seiriol at Penmon. Some religious poetry is attributed to him, as is the foundation of St Eleth's Church, Amlwch, also in Anglesey.