The priory and parish church of St Mary in Chepstow (Cas-gwent) in Monmouthshire dates from the late 11th century. The priory was founded in 1072 by the Benedictines, later the nave of the church became the parish church. After the Dissolution of the priory in 1536 the other priory buildings around the church were demolished, the choir church and chapterhouse were also lost.
Although parts of the original Norman church remain, including the main doorway, there have been a lot of changes to the church over the subsequent centuries. The church originally had a central tower which collapsed in 1701, destroying the tower and the transepts. A new west tower was built to replace it over the Norman doorway. The church is built from local yellow sandstone, rubble and ashlar.
