The tower is a modest structure, roughly 3.5 metres by 2.75 metres externally, and close reading of its fabric reveals something telling: the doorway punched through its eastern wall into the body of the vanished church cuts through older stonework and was later repaired with brick, and the tower itself is partially blocking two window lights in the church's west wall. That detail, small as it sounds, places the tower as a later addition to the original building rather than a part of its founding design. The ghost of the church roof is still legible as a pitch-mark on the tower's eastern face, along with traces of a large window near the apex.

The church here was the medieval parish church of Clontibret, and its patron was a St Colmán whose feast falls on either 30 September or 13 June, depending on which martyrology you consult. Scholars have suggested he may be a localised expression of St Colum Cille rather than a fully independent figure. The parish appears in the ecclesiastical taxation of Pope Nicholas IV, compiled between 1304 and 1306, grouped with other parishes of Cremorne barony under the older territorial name Crichmugdorn. Named clergy associated with the site are recorded from 1424. By the time of Bishop Spotiswood's visitation in 1622, the church was already ruinous, and a Royal Visitation in 1667 found it in no better condition. Samuel Lewis, writing in 1837, still described the remains as a plain old structure with a square tower capped by a spire. Two years later, in 1839, the present Church of Ireland building dedicated to St Columba was erected just to the north of those surviving fragments.

The graveyard holds headstones going back into the eighteenth century, the earliest dated 1717, and local tradition holds that an even earlier church once stood to the west of the road that now forms the graveyard's western boundary, beyond the current enclosure altogether. That earlier site, if it existed, has left no visible trace, which makes the tower and the partial west wall of the medieval church the oldest things you can actually stand beside here.