Supposed king of Tara, son of Niall Nofgiallach, and progenitor of Cenel Loeguiri, a dynastic group which, according to their own genealogical tradition, were powerful in Ireland during the sixth and seventh centuries, ruling territories which extended from Loch Erne to the church of Rathlihen, north of the Sliabh Bloom Mountains. The dynasty’s main power base seems to have been near the church of Trim in modern county Meath. Very little can be said with certainty about Loegaire because all accounts of his activities considerably postdate his lifetime.
According to the annals and other sources, Loegaire’s floruit was in and around the second third of the fifth century. However, there are some indications that he may, in fact, have lived as early as the fourth century. The fifth century chronology for Loegaire may have originated in the church of Ardbraccan, in Cenel Loegaire, which seems to be the source of the Loegaire episode in Tfrechan’s late seventh century collection of lore about St. Patrick. That church wished to associate the founder of the local dynasty with the saint, the date of whose arrival in Ireland had been set at 432.
Loegaire plays a prominent role in the seventh century Patrician hagiography, where his supposed encounter with Patrick at Tara is a central element of the narrative. According to Muirchu, Loegaire converted to Christianity following his encounter with St. Patrick. Tirechan, on the other hand, says that he refused to accept the Christian faith, because his father, Niall, would not allow this; he had ordained that Loegaire should be buried, fully armed, in the ridges of Tara, facing the graves of Ui Dunlainge of Leinster— traditional enemies of the Ui Neill—at Mullaghmast in County Kildare. This hostility is reflected in the annals—written long after Loegaire’s lifetime—which recount that Loegaire routed the Laigin (Leinstermen) in the year 453. Fortunes were reversed five years later at the battle of Ath Dara when Loegaire suffered a defeat at the hands of the same enemy; he was taken prisoner and released only when he gave the elements as sureties that he would cease to levy the Boruma Laigen ("the cattle tribute of the Laigin"). A tract on the Boruma recounts that Loegaire broke his promise and the elements, accordingly, passed judgement on him and brought about his death. The account of his death in the annals—at the year 462—refers to this legend.
Presumably because of his association with St. Patrick, the pseudohistorical prologue to the Senchas Mar (the major collection of Brehon Law tracts) claims that Loegaire called a convention of the men of Ireland to reform the traditional laws in accordance with Christianity.
The Bansshenchas names two wives of Loegaire as Angas, daughter of Ailill Tassach of the Eoganachta of Munster, and Muirecht, daughter of Eochaid Munremar, an ancestor figure of the Dal Riata of Antrim and Scotland. Genealogical accounts dating from different periods ascribe between twelve and fifteen sons to Loegaire.
