The church here was not built in stone but in wattle, and it left behind not walls but a pattern of post-holes and a compacted clay floor, surviving only as traces in the earth until excavation finally brought it into focus.

When archaeologists dug here in 1974, they uncovered a small rectangular structure measuring 5.5 metres by 4.1 metres, its walls defined by rows of wattle- or stake-holes rather than any masonry. Wattle construction of this kind was common in early medieval Ireland, using interwoven rods or stakes as the structural framework, sometimes packed with clay or reinforced internally, as appears to have been the case here, with close-set wattles serving as internal strengthening. The building had an entrance through the west wall and a trodden clay floor. What makes the sequence especially interesting is that the structure was rebuilt several times, and with each rebuilding the orientation shifted, first swinging towards an almost north-east to south-west alignment and then correcting back towards the conventional east-west axis. The earliest phase shared its precise orientation with St. Brigid's church elsewhere on the island, a detail that suggests some deliberate planning or shared tradition at the site's foundation. The archaeologist Liam de Paor interpreted this building as representing the earliest phase of the monastery on Inis Cealtra. Adding another layer to the timeline, the church was eventually cut through by a medieval house built over the same ground, one structure quietly erasing, or at least overwriting, the memory of the other.