1. The parish of Hay was separated from the pre-Norman parish of Llanigon in the 12th century at which time the tithes of the manor of Hay were bequeathed to the new church of St. Mary by William Revel, lord of the manor.This deed still exists among the Carte manuscripts in the Bodleian Library at Oxford. The church was built on a mound above the river Wye, west of the Login brook and as was customary was sited close to the castle, which was a motte and bailey on the tump near the present cattle market. This explains why the church is outside the mediaeval town walls, which were not built until 1237, after the second and larger castle was completed.
[Source: A History of the Hay by Geoffrey L. Fairs, Phillimore, 1972]
2. St Mary's church lies on the western side of the town of Hay, immediately to the south of the River Wye. The church may have been founded early in the 12th century, but only the tower of the medieval structure remains, the rest having been rebuilt in the 19th century. It contains some interesting Victorian features including its gallery and an elaborate pulpit, but from the middle ages only a worn effigy has survived. The churchyard is triangular in shape and perhaps fossilises an earlier and smaller yard of similar design. The tower is 15th century, but its battlemented top is 19th century. The nave and chancel are completely 19th century, though of two different periods.
[Extracted from Clwyd Powys Archaeological Trust (CPAT) website]
3. The original 12th century church, presumably later much extended, collapsed circa 1700. Only the embattled 15th century west tower, a defaced effigy, and a tablet to Elizabeth Gwynn, d. 1702, predate the church of 1834 with additions of 1866.
[Extracted from The Old Parish Churches of Mid-Wales by Mike Salter, 2nd edition published 2003, Folly Publications, Malvern; ISBN 1-871731-62-3]
4. The original 12th century church had suffered years of neglect by absentee vicars, until in 1828 it was described as "...dark, comfortless and ill-contrived, and quite inadequate in point of size". [Description extracted from the Way on High local parish magazine website, which appears to be no longer online (August 2014)]