Burnt in 1265, suppressed in 1542, largely demolished by Cromwellian forces in 1653, and yet the church continued to function in some capacity through all of it, accumulating centuries of damage and repair in roughly equal measure. Restoration work was carried out in 1846, 1889, 1899, and again in the early 1960s, each intervention leaving its own trace on a building that was already a patchwork of medieval ambition and violent interruption.

The abbey was founded in 1216 by Cathal Crovderg O'Connor, on the site of an earlier monastery, for the Augustinian Canons, a religious order whose members followed the Rule of Saint Augustine and lived in community rather than in the more enclosed tradition of the Benedictines. Bricius served as the first abbot. The church is cruciform in plan, forty metres long and nearly twenty-three metres across its transepts, with chancel, nave, north and south transepts, and two side-chapels off each transept, all dating to the thirteenth century. Four pointed arches at the crossing originally supported a low crenellated tower. The chancel retains low ribbed vaulting on well-carved capitals, two piscinae (small stone basins used for disposing of water used in the Mass), and a sedilia, the recessed stone seating built into the south wall for the officiating clergy. Three transitional windows, mixing Romanesque and early Gothic forms, light the east wall above the main altar. The western doorway dates to the fifteenth century and was reinserted in 1964. South of the chancel stands a seventeenth-century mortuary chapel associated with the de Burgo family, and the chapter house, where the monastic community would have met daily, preserves a fine thirteenth-century doorway on its eastern side. Walter Mac Evilly was the last abbot at the time of the Tudor suppression in 1542; by 1605 the property had passed to a John King, though the Augustinian friars regained possession sometime in the mid-seventeenth century.