Known correctly as Teampall na Naomh, meaning the Church of the Saints, it is a small ruined nave and chancel church measuring just over ten metres in length and a little under six and a half metres wide. What marks it out is the quality of its architectural detail: a Romanesque doorway set into the west wall, round-headed windows in the east and south walls, and a projecting corbel at the north-east corner of the chancel. Romanesque architecture in Ireland generally dates from the twelfth century, when continental influences began to shape the decoration of church doorways and arches, and Teampall na Naomh preserves several of these features in compact and legible form.

The church lies roughly 75 metres south-east of the older St Patrick's church, the island's other principal monument. Between them the two buildings suggest a site of some sustained religious importance over several centuries. Particularly striking is a decorated cross-slab that has been incorporated into the west end of the south wall of the nave; cross-slabs of this kind are among the earliest forms of Christian commemorative carving in Ireland, and the decision to build this one into the fabric of the wall suggests it was already considered significant when the church was being constructed or modified. The plain chancel arch, the modest scale, and the careful placement of the slab together give the ruin an atmosphere of considered rather than showy piety. Scholars including O'Flanagan and Fahey had noted and described the church by the early twentieth century, and Harold Leask included it in his influential survey of Irish churches published in 1955.