In ogham, the ancient Irish script carved as a series of notches and strokes along the edge of a stone, "ANM" is a formula meaning "name of", so the inscription reads, simply, "the name of Tegann, son of Deglann." That is all. No date, no deed, no rank. Just the fact of a person having existed.

The story of how this stone reached its current home is almost as interesting as the inscription itself. According to the scholar R.A.S. Macalister, writing in 1945, the stone and a companion piece were lifted from a souterrain, an underground stone-lined passage typically associated with early medieval ringforts and used for storage or refuge, belonging to a fort known as Lisnareabh. The land was occupied at the time by a man named Foley, an innkeeper from Killorglin, who showed the stones to John Windele, the Cork-based antiquarian with a well-documented habit of acquiring ancient objects and removing them southward. Windele duly took both stones to Cork. A ringfort called Lisnareabagh still appears on the Ordnance Survey six-inch map of Tinnahally townland, and it contains a souterrain, making it the most plausible original location for the stones. One of the pair eventually found its way into the collection of the Royal Irish Academy; this stone, measuring 1.77 metres in length, is now held at the National Museum of Ireland.

The stone has since been digitally recorded as part of the "Ogham in 3D" project run by the School of Celtic Studies at the Dublin Institute for Advanced Studies, which is building a comprehensive three-dimensional archive of surviving ogham inscriptions across Ireland and beyond. The physical stone itself can be seen at the National Museum of Ireland, while the ringfort at Tinnahally, where Tegann and Deglann may once have been remembered in person, remains in Kerry.