Situated in the town of Clonmel, County Tipperary, Old St. Mary's Church is believed to have been built by William de Burgo in 1204.
In the late-14th to early-15th century, a fortified church was constructed on the site. The base of the bell tower and the east tower house survive from that house of worship, which was largely destroyed in 1650 during the Cromwellian occupation.
In 1805, the structure underwent major renovations and the 25m-high octagonal bell tower was built on the base of the original tower.
Old St Mary's is still use by the Church of Ireland.