Found at Cathair na Máirtíneach, a roughly circular cashel (a type of dry-stone ringfort) on the lower southern slopes of Mount Eagle overlooking Dingle Bay, the stone bears three carved motifs: a circle, an equal-armed cross, and a cross-in-circle. Markings of this kind appear on early medieval stonework across Ireland and western Britain, usually associated with Christian communities from roughly the sixth century onwards. What makes this particular stone unusual is not what is carved on it, but the cloud of suspicion that has hung over it ever since it came to scholarly attention.

When the antiquarian R.A.S. Macalister investigated the site in 1899, he was told locally that the stone had been found inside one of the internal structures of the cashel. Rather than accepting it as a genuine early medieval artefact, however, Macalister concluded it may have been a fake, manufactured relatively recently and planted within the site. The cashel itself is a substantial enclosure whose interior holds the remains of several structures, all of which have changed considerably from their original form, making it difficult to read the archaeology with confidence. The stone has since been removed to the National Museum of Ireland, which means the debate about its origins has outlasted its presence at the site. Whether Macalister was right to be sceptical, or whether he dismissed something genuine on insufficient grounds, remains an open question.