That wall is not a later curiosity or a structural accident; it was built deliberately in the late sixteenth century to convert the western half of the building into a priest's residence, leaving only the eastern end functioning as a place of worship. The arrangement means that a single ruin contains what are effectively three buildings collapsed into one: a Romanesque nave, an early Gothic chancel, and a domestic partition wall, each from a different century, each still legible if you know what to look for.

The Annals of Innishfallen record the completion of 'the great church of Aghadoe' in 1158, a date that fits the western end of the structure, where a Romanesque doorway, round-arched in the manner typical of twelfth-century Irish ecclesiastical building, is decorated with cut sandstone ordered in four concentric arches. The carved detail is unusually elaborate: one order carries chevrons and a column with a 'double embattled' motif, another has beading and an 'ovoid leaf' capital, and the outermost label bears a 'ball' motif. At least the two outer orders of the arch are not original, having been altered by the Commissioners of Public Works, who repaired the structure on at least two occasions, most recently in the 1930s. The eastern end, built sometime in the early thirteenth century, is distinguished by a pair of identical round-arched windows set side by side in the gable, covered together by a single semi-elliptical relieving arch. Between the two windows, near the top of their shared vertical edge, a single stone carries two carvings: a human face on one side, a geometric knot on the other. An ivory crozier head was found somewhere inside the church, though the precise circumstances are not recorded.

The graveyard that surrounds the church is densely occupied, both inside the walls and immediately beyond them, with burial plots crowding the interior. Resting on the reduced southern wall, near its eastern end, is an ogham stone, ogham being the early medieval Irish script carved as a series of notches along a central line. Nearby are two further carved stones, one bearing a crucifixion scene and another a stylised flower. Just outside the north-west corner of the church sits a bullaun stone, a large boulder with one or more cup-shaped hollows ground into its surface, whose precise function remains debated by scholars. Some eighteen metres to the north-west stands a round tower, the tapering stone structure used in early medieval Ireland as a bell tower and place of refuge. The accumulation of all these elements in one graveyard, spanning perhaps a thousand years of use, gives the site an unusual density even by Irish standards.