Diarmait Mac Cerbaill - Grandsons of Neill, Tribe of Conn

Grandsons of Neill, Tribe of Conn

According to later writings, Diarmait was the son of Fergus Cerrbél, son of Conall Cremthainne, son of Niall of the Nine Hostages. As a great-grandson of Niall, he and his descendants were counted among the Uí Néill. The Uí Néill as such, the name means "grandsons of Niall", can only have existed in the time of Niall's grandsons, but its common usage may be later yet as an earlier term moccu Chuinn is attested as late as the time of Saint Columba (died c. 597), a great-grandson of Niall's son Conall Gulban. This, incorporating the Primitive Irish language gentilic or demonym moccu—the masculine term, the feminine is dercu—indicates membership of the tribe of Conn, presumed to be named for Conn of the Hundred Battles, a legendary figure, or perhaps a euhemerised divinity, claimed as the ancestor of the Connachta. Moccu was later often misread or misunderstood by later writers, for whom gentilic names were alien and parentelic ones familiar, as a compound of mac and ua—son of the grandson of someone—an error likely to have resulted in many later genealogical confusions as members of the same tribe were turned into cognatic blood relatives.

As for the reality, Byrne says: "Diarmait's immediate origins are obscure and may arouse some suspicion." He notes that Adomnán calls Diarmait filius Cerbulis, son of Cerball, and not son of Fergus as the genealogies would have it. The same applies to other hagiographical materials, which again have Diarmait as the son of an otherwise unknown Cerball. Also likely to raise suspicion that Diarmait's genealogy is a later fiction, is the fact that unlike the majority of the Uí Néill, who traced their descent from, and were named for, sons of Niall, Diarmait's descendants were named for his sons.