A church at Llandegfan was recorded in 1254, probably where St Tegfan had established a cell in the 6th century.
This is a large and handsome town church, built in the early 14th century, with additions in the 15th century.
Many of the objects of interest in the church came from nearby Llanfaes Priory. The most notable is the stone sarcophagus of Princess Joan, wife of Llewlyn the Great and daughter of King John. It was used as a horse trough at the Dissolution of the Monasteries. Also from Llanfaes are the carved misericords, many depicting women.
There is a very fine alabaster effigy to William Bulkeley.