Its importance was as an embarkation point for the abbey on Bardsey Island which became a significant site of pilgrimage in the Middle Ages.

In the 1850s a new church, Eglwys Newydd, was constructed inland, but proved so unpopular that St Hywyn's was restored.

[1] The clas was founded by St Hywyn, an early Welsh Saint originally from Brittany.

[3] The writer Simon Jenkins notes that visits to both sites equated to a single pilgrimage to Rome.

[7] Two carved boulders within the church commemorate a pair of 5th or 6th century priests, Veracius and Senacus.