Though not listed in any extant Irish genealogies, the Annals of Innisfallen record his death at the battle of Mag Femen in the kingdom of Brega in 446.
Almost uniquely, this otherwise unverifiable reference is corroborated by an Ogham inscription on a stone near Slane in the neighbouring County Louth.
It reads MAQI CAIRATINI AVI INEQAGLAS, which translates as [the stone] of Mac Cairthinn grandson [or perhaps descendant] of Enechglass.
This appears to be based on the false assumption that his father was the eponymous ancestor of the Dál nAraidi sept of Uí Chóelbad.
Other unreliable and late sources may have linked Mac Cairthinn with the Uí Néill, by making his father Cóelbad a son of Niall.