It belongs, architecturally, to the west wall of a 12th-century Romanesque church, but during a late rebuilding, probably around 1683, it was lifted out and reset in the wrong wall entirely. The lancet window that once sat above it was moved too, and replaced inexactly. What visitors see today, then, is a building that has been partially shuffled, its finest carved element relocated and its proportions quietly reorganised, while the lower courses of cyclopean masonry, very large undressed stones laid without mortar in the early medieval manner, remain from something far older underneath.

St Tola founded a monastery on this low-lying site around AD 700, and the ground has accumulated layers of building ever since. The 12th-century Romanesque church that once stood here had a decorated west doorway and a plain chancel arch; three narrow lancet windows were added to the east gable early in the 13th century. At some point the whole structure fell into decay, and the reconstruction that followed reused and rearranged what survived. The relocated doorway is the most striking result of that process: four orders of carved stonework decorated with 19 heads, human and otherwise, alongside geometric motifs and foliage, all framing an entrance that was never originally intended to face south. The round-headed Romanesque window in the west wall was similarly reconstructed from elements of several earlier windows, leaving a surrounding of unrelated carvings that do not quite belong together. Inside, the chancel wall carries a 17th-century monument commemorating Joan O'Dea, and a slab from what may be a 14th-century effigial tomb was once fixed to the exterior wall beside the doorway. A blocked-up doorway high in the north wall faces, pointedly, towards the remains of a round tower that still stands just two metres to the north-west, while the high cross of St Tola lies in the field immediately to the east, re-erected on corner stones robbed from the church itself, probably in that same year of 1683.