That anyone should use ogham stones, each one carrying a personal name cut in the ancient Irish script of notched lines along an edge, as building rubble is quietly remarkable. At Ballyknock in County Cork, that is precisely what happened, and the stones only came to light because someone, at some point, went looking beneath the surface.

The stone in question is a broken piece of slate, roughly two feet eight inches tall and a foot eight by six inches in cross-section, snapped from the upper portion of a larger original. Its inscription runs along the dexter edge and across the top, the dexter edge being the right-hand side of the stone as it faces the reader, which is the standard position for ogham. Two scholars have attempted to resolve what it says. R. A. S. Macalister, whose monumental catalogue of Irish ogham inscriptions was published in 1945, read it as LAMADILICCI MAC MAIC BROCC, a formulaic ancestral declaration of the kind common to these stones, naming a person as the son or grandson of Brocc. Damian McManus, working from the same stone in 2004, arrived at a slightly different transcription: L[A]MaDULICCi MAC[]CBROC. The divergence is modest but telling; ogham can be genuinely difficult to read, and worn or damaged stones leave room for disagreement even between careful specialists. The stone is now held at University College Cork, displayed in the Stone Corridor, a long gallery that houses one of the largest collections of ogham stones in the world, where the Ballyknock piece sits among others gathered from across Munster.