The church was originally built as a chapel for the almshouses and the girls' school, as well as for the free use for any who chance to come to it especially the Poor of the Town of Abergavenny. Of the 600 seating spaces, only 72 were thus subject to the (then customary) pew rents, which many churches charged, thus visibly reenforcing the prevailing class structure through public worship. In comparison, the Parish Church of Abergavenny (The Priory Church of St. Mary) charged pew rents on 1,060 of its available 1,606 spaces.
Church building was much smaller than it is now when it was consecrated in 1840 by the Bishop of Llandaff, Dr. Copplestone. The original church building consisted of the Nave with its Western gallery and a small Chancel. This all changed when in 1866 the Bell Cote was moved from the East end of the Nave to the West, directly above the Gallery. The Chancel and Sanctuary were extended, and the Sacristy and Organ Chamber were constructed in 1885. It was another