A reset Romanesque doorway is found inside the W wall of this Church of Ireland parish church (now used jointly as Church of Ireland and Roman Catholic parish church). The reset doorway is said to come from the Cistercian Abbey that once stood on this site.

Inislounaght was founded as a daughter house of Mellifont in 1147/8, and transferred to Monasteranenagh in 1151. The first abbot was a disciple of St Malachy and friend of St Bernard. In 1187 it was re-endowed by Domnall Mór Ua Briain. In 1227 it was made subject to Furness. Following the Dissolution, the abbey buildings began to be quarried c. 1670s when stone from them was used to construct the Main Guard in Clonmel. Substantial remains of the buildings survived until 1818 when the present church was constructed. Together with the doorway it incorporates ashlar with 12thc. tooling and mason's marks and a 15thc. window.

The Romanesque doorway probably belonged to the original church. The keeled roll mouldings and scallop capitals suggest a date c.1180-1200.