Sometime in the early medieval period, a stone was inscribed with a string of notched marks along its edge and set up, most likely, as a grave marker. Ogham, the earliest form of written Irish, works by scoring a series of lines and notches across a central stem, usually the corner of an upright stone, to represent letters. The stone found in Donaghmore graveyard in County Kildare had been doing quiet double duty for centuries: when Lord Walter Fitzgerald came across it in 1902, it was still in the north-east corner of the graveyard, apparently serving as a marker for an O'Farrell family grave, its original purpose long absorbed into a later one.

Fitzgerald published his discovery in the early 1900s, and the stone was later examined by the scholar R.A.S. Macalister, who recorded its dimensions as roughly 76 by 36 by 23 centimetres and read the inscription as NETTAVRECC [KOI] MAQI MUCCOI TRENALUGGO. In ogham, MAQI means "son of" and MUCCOI indicates a tribal or kin group, so the inscription follows a well-established Early Christian formula: a personal name, a patronymic or lineage marker, and a tribal affiliation. The name NETTAVRECC and the group name TRENALUGGO are the specifics here, though even those details have been contested. Damian McManus, writing in 1997, argued that the spacing on the stone left room for a more probable reading of NETTAVROICC or NETTAVROECC, and that Macalister's bracketed KOI was likely a misreading. These are not pedantic disputes: in a writing system where a single notch can change a name entirely, the difference between one reading and another carries genuine weight for anyone trying to trace early Irish genealogies or place-names. The stone is now held in the National Museum of Ireland in Dublin, where it has moved from graveyard curiosity to catalogued artefact.