The Priory and Parish Church of Saint Mary is in Beddgelert. It is a Grade: II* Listed Building, on the site of one of the oldest Christian establishments in Wales. An early Christian community was established there in the 6th century AD which is mentioned by Gerald of Wales. An Augustinian priory was founded there in the 13th century and in the Middle Ages it grew substantially thanks to the support of important Welsh nobles including Prince Llewelyn.
The priory and many of its records were destroyed in 1283 or 1284 by a fire. In the 16th century, following the dissolution of the monasteries, the priory became a simple parish church. Remnants of the church's medieval past include transept arches and some of the stonework around the lancet windows. The Victorian era brought further modifications including the demolition of the north aisle and some new stained glass. The existing glass is dated only to the 19th and 20th centuries and includes work by Dunstan Powell and Trena Cox (1968).