St Seiriol's Priestholm on Puffin Island

by Max Pemberton
(Anglesey)

When St. Seiriol founded the Penmon Monastery he also set up a community on a small island just off the coast, half a mile from the shore.

Today this island is more popularly known as Puffin Island. The Vikings called it Priestholm, a clear reference to it's ecclesiastical history.


Seiriol is also reputed to have had a chapel in Penmaenmawr, a settlement to the south across the Lavan sands, on the mainland.

And ancient records describe his route between two hermitages, along a tract of sea marsh and sand once said to connect Puffin Island with the mainland.

The island has a number of medieval monastic ruins, including a 12th century church tower.

It is said that St. Seiriol was buried here before his remains were transferred to the Priory.

Some speculate that perhaps King Maelgwn Gwynedd, ruler of North Wales c.534 to c.549, and patron of St.Seiriol in establishing a religious community, was also buried here.

An interesting record relating to this period is cotained in the chronicles of Basingwerk Abbey: "Maelgwyn, King of Britain was buried at Ynys Seiriol (Puffin Island). He made the Priory at Penmon."

The Annales Cambriae record that in c629 Edwin of Northumbria, recognised as overlord by all the other Anglo-Saxon kings of his time, beseiged King Cadwallon of Gwynedd on the island of Glannauc (Puffin Island) as part of a prolonged war between the two.

Seiriol's Island is also mentioned by Geraldus Cambrensis (Gerald of Wales) in his Journey through Wales in 1188.

He notes that it is an ecclesiastical settlement at this time, "inhabited by hermits, living by manual labour and serving God".

He also says that no women were allowed on the island and, according to legend, whenever there was strife within the community a plague of small mice (or rats, depending on which story you read) would eat up all their food.

An inclined plateau of limestone, it has also be called Ynys Lanog, Ynys Glannauc and Ynys y Llygod (Rat Island).

Its relatively modern name of Puffin Island derives from the vast number of puffins which settled there.

Numbers have steadily declined because of rats and because puffins, once considered a delicacy, were pickled in small barrels and shipped to England and France.

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