What is "peulan"

Saint Peulan was a Welsh holy man in the early part of the 6th century, the son of Paulinus, a saint from south Wales who taught Saint David. A follower of Cybi, a saint associated with the island of Anglesey in north Wales, Peulan is commemorated in the dedication of the church he reportedly founded, St Peulan's Church, Llanbeulan, on Anglesey.