Demmán mac Cairill (died 572) was a king of the Dál Fiatach, and over-king of Ulaid in Ireland. He was the son of Cairell mac Muiredaig Muinderg (died 532), a previous Ulaid king and brother of Báetán mac Cairill (died 581).Byrne, Table 6; Charles-Edwards, appendix XXI; Mac Niocaill, pg.74 He ruled the Dál Fiatach and Ulaid from 557 to 572.the Book of Leinster gives him a reign of 11 years and Laud Synchronisms 14 years
Background According to the genealogies, he was fostered by a certain Domangart mac Predae, possibly Domangart Réti, King of Dál Riata.Ó Cróinín pg.216 He acquired the kingship of Ulaid by defeating and slaying Fergnae mac Oengusso Ibdaig at the Battle of Druim Cleithe (Kilclief, modern County Down, Northern Ireland) and had the support of the Uí Echach Arda.Annals of Ulster AU 557.1; Annals of Tigernach AT 556.2; Ó Cróinín pg.216-217 He himself was slain by the shepherds of Boirenn.Annals of Ulster AU 572.3; Annals of Tigernach AT 567.1
He was married to Garbae ingine Néilléne of the Cenél nEógain. He had five sons including Fiachnae mac Demmáin (died 627), a later king of Ulaid. His descendants the Clan Demmáin went on to monopolize the kingship of the Dál Fiatach. His fort, Ráth Deamáin, stood just west of Crossgar in what is now the townland of Rademan in the parish of Kilmore, County Down, Northern Ireland.
Notes
See also Dál Fiatach Kings of Ulster Ulaid
References
Annals of Ulster at at University College Cork Annals of Tigernach at at University College Cork Byrne, Francis John (2001), Irish Kings and High-Kings, Dublin: Four Courts Press, Charles-Edwards, T. M. (2000), Early Christian Ireland, Cambridge: Cambridge University Press, Gearoid Mac Niocaill (1972), Ireland before the Vikings, Dublin: Gill and Macmillan Dáibhí Ó Cróinín (2005), A New History of Ireland, Volume One, Oxford: Oxford University Press
External links CELT: Corpus of Electronic Texts at University College Cork