St. Mary's was a priory church of Chertsey Abbey. Benedictine monks cared for it until 1538, when they were expelled and the shrine destroyed.

Devotion to Mary was once universal in Wales. Many places are called Llanfair or Capel Mair (Mary's church, chapel), and dozens of flowers and plants bear her name. No girl was given the name Mair (Mary), as it was reserved for Our Lady.