That quiet fact gives the stone a small but genuine curiosity: it exists in the historical record without ever having appeared in the plan drawn up to document its surroundings.

The slab measures 1.5 metres in length and 0.43 metres in width, undecorated and unremarkable to the eye, positioned roughly towards the centre of the enclosure, 14.1 metres from the southern wall and 10.7 metres from the western one. When R.A.S. Macalister surveyed the Saint's graveyard in 1916 and 1917 and published his plan of the site, this particular stone did not appear on it. Whether it was obscured, overlooked, or simply not yet visible at the time of his visit is not recorded. Macalister was a prolific surveyor of early Christian and prehistoric monuments across Ireland, and his plans of island sites like Inis Cealtra were considered thorough for their era, which makes the omission all the more quietly puzzling. Inis Cealtra itself is an early medieval monastic island, its remains including churches, a round tower, and a collection of graveslabs that together reflect centuries of use as a place of burial and religious life.