The church tower dates to 1760, built onto an earlier structure, and the whole was rebuilt again in 1809, but what lies beneath and around it remains genuinely uncertain. The earliest surviving headstone, found broken against the south wall, is dated 1730, and only two other eighteenth-century stones are known; the graveyard is otherwise dominated by nineteenth-century memorials, which gives the site a slightly odd chronological silence for a place with such a long claimed history.

The parish church of Nenagh is attributed by tradition to St Colman and appears in a deed of around 1217 to 1221, at which point the advowson, meaning the right to appoint the clergy, was jointly held between the Butler family and the abbots of Abingdon in County Limerick. By the time of a Royal Visitation in 1615, the church was already described as 'ruynous, chancell downe', and its precise medieval location has never been established. A later account from the Ordnance Survey Letters noted that 'not a vestige' of the original parish church remained, though the author suspected the then-modern church stood near or on its site. That same account records a striking discovery made by a local man, Mr Rd. Burr, who found, about eighteen inches below the surface of the ground near Barrack Street, the foundation stones of a curved-ended building with walls four to five feet thick. The stones had already been removed by the time it was described, but the dig also produced a bronze ring-seal, an object whose origins and whereabouts are not further recorded. The Franciscan friary and Nenagh Castle lie just to the north and north-west, making this corner of the town one of the more archaeologically layered parts of an already historically dense settlement.