Ogham is an alphabet of grooves and notches cut along the edge of a stone. It uses a vertical line - usually a corner where two faces meet - as its baseline, and adds short strokes above, below, or across it to indicate letters. The system was developed in early Ireland, possibly in the third or fourth century, by people whose contact with the Roman world had taught them the value of writing. Ogham was not used for long texts. It appears almost exclusively on standing stones, recording short formulae that name a person and sometimes their lineage. A typical inscription reads X son of Y, or X grandson of Y. The strokes are read from bottom to top, then across the top, and sometimes down the other side. Around four hundred such stones survive in Ireland, mostly in the south and southwest. The Ballintaggart cluster is one of the densest and most studied collections.

Eight of the Ballintaggart stones lie in a circle, each pointing outward. The ninth sits at the centre. Several have been incised with crosses in addition to their ogham inscriptions - the crosses added centuries later, when the same site was reused as an early Christian burial ground known as An Ceallunach or An Lisin. The exact arrangement is unusual. Most ogham stones stand upright, in singletons or small groups, as boundary markers or grave markers above an individual burial. The Ballintaggart pattern - a circular ring of recumbent stones around a central one - suggests something more like a constructed memorial space, possibly the deliberate gathering of stones from elsewhere by a later community wishing to consolidate the markers. The site sits within a round enclosure roughly thirty metres across, immediately east of Dingle racecourse on the slope above the harbour town.

Each stone has been catalogued by Macalister in his Corpus Inscriptionum Insularum Celticarum, the standard reference for ogham. Stone CIIC 155 reads AKEVRITTI, presumably a personal name. CIIC 156 reads MAQQI-IARI KOI MAQQI MUCCOI DOVVINIAS - here is Mac-Iair, son of the Corcu Duibne, the very people who gave the Dingle Peninsula its name. CIIC 157 reads DOVETI MAQQI CATTINI - of Duibthe, son of Caitne - in a Primitive Irish so early that the vowel system has not yet softened in the way it would by the seventh century, placing the inscription around the time of Saint Patrick. CIIC 158 names Suvallos son of Ducovaros. CIIC 159 records a grandson of Glasiconas, a name that translates roughly as Grey Wolf. CIIC 160 commemorates the three sons of Mailagnas, with the name Cuircthe also inscribed. CIIC 161 reads INISSIONAS, another early personal name. CIIC 162 names Conmac grandson of Corb. CIIC 163 reads NETTA-LAMINACCA KOI MAQQI MUCOI DOVINIAS - here is Laminacca's champion, son of the Corcu Duibne.

The dating matters. Some of these stones - particularly CIIC 157 and CIIC 161 - are in a form of Irish so early that linguists place them around the mid-fifth century, the lifetime of Patrick. That makes them the oldest pieces of Irish writing in this part of Kerry, and among the oldest in Ireland. The men named on the stones - and they are all men, as far as we can read - belonged to the kingdom of the Corcu Duibne, the people of Duibne, the Iron Age and early medieval tribe that ruled the Dingle Peninsula. The fact that two of the Ballintaggart inscriptions explicitly name the Corcu Duibne lineage tells us something about identity in fifth-century Kerry: a man was his father's son, but also his people's son, and the latter affiliation deserved chiselling in stone.

Visiting Ballintaggart today is a quiet experience. You park beside the racecourse, walk through a gap in the hedge, and find yourself inside the round enclosure with nine sandstone boulders lying in the grass. A small interpretive panel translates some of the inscriptions. The stones are dark and heavy and, in the right light, you can run a finger along the edges and feel where the ogham strokes were cut. The names are still legible. AKEVRITTI. DOVETI. NETTA-LAMINACCA. They belonged to people who lived sixteen hundred years ago and who, in the act of carving their names into stone, asked only that they be remembered. They have been. Their kingdom - the Corcu Duibne, whose name lives on in Corca Dhuibhne, the Kerry Gaeltacht - still exists as a place. Their language, the Primitive Irish that even Patrick would have recognised, has been continuously spoken in these hills longer than almost any vernacular in Europe.