Fiachnae mac Baetain, also known as Fiachnae Lurgan, was a member of the Dal nAraidi, the main dynasty of the people known as Cruithni. The Dal nAraidi kings, including Fiachnae, resided at Raith Mor in Mag Line (Moylinny), east of Antrim town. Along with another Cruthni dynasty they supplied a number of over kings of Ulster between the sixth and the tenth centuries. However, most kings of Ulster were supplied by the "true Ulaid," of which the Dal Fiatach in eastern Down were the ruling dynasty. Fiachnae mac Baetain’s main enemy in Ulster was Fiachnae mac Demmain of the Dal Fiatach dynasty. After winning many victories over his rival, Fiachnae mac Baetain was finally defeated and slain by him in 626.
According to the Annals of the Four Masters, Fiachnae, whose rule was to span more than three decades, killed Aed Dub mac Suibni and succeeded him in the Ulster kingship in 588. In 597, in one of his many recorded victories in the Annals of Ulster, Fiachnae was active as far south as Slfab Cuae in Munster. In the Book of Leinster under Rfg Ulad (kings of Ulster) Ffachnae mac Baetain can be found between Aed Dub and Fiachnae mac Demmain as well as under the heading Rig Dail Araide (kings of Dal nAraidi).
We may deduce from this that Fiachnae was an important and powerful king, but is it possible that he achieved the ultimate title, that of King of Tara? Fiach-nae is not included in Middle-Irish Tara king-lists, while several suspect Uf Neill dynasts are. The earlier Baile Chuinn (Conn’s vision) king list, on the other hand, omits many of these Uf Neill kings from the late sixth and early seventh centuries. In their place it includes some unidentified names, such as Fechno. F. J. Byrne suggests that "it is not altogether impossible that he [Fiachnae mac Baetain] is the mysterious Fechno who appears as Diarmait mac Cerbaill’s successor to the high-kingship of Tara in the Baile Chuind." Some middle-Irish sagas would certainly seem to agree with this suggestion. One such tale actually states that Fiachnae was king of Ireland and Scotland. It may be concluded that Fiachnae mac Baetain was a powerful Ulster king who extended his influence across the sea and into the midlands and south of Ireland to such an extent that he may at least have been a contender for the kingship of Tara.
In addition to the historical record, Ffachnae appears in the literature as father of the enigmatic Mongan mac Fiachnai. In the tale Compert Mongain, Ffachnae goes to the aid of his ally Aedan mac Gabrain, king of Dal Rfata in Scotland, in a war against the Saxons. In his absence the god Manannan mac Lir visits his wife and Mongan is conceived. The fact that a cycle of tales was composed depicting Fiachnae’s son Mongan as an extraordinary figure may be due to some degree to the extent of Fiachnae’s power combined with his alleged relationship with the poets of the time.
