O'Connor (Ó Conchobhair), Domhnall

by Emmett O'Byrne

O'Connor (Ó Conchobhair), Domhnall (d. 1395), lord of Carbury, was the son of Muircheartach O'Connor (d. 1329), a brother of King Cathal (qv) (d. 1324). After the death in 1362 of Cathal Óg O'Connor (qv), lord of Carbury, he emerged as a significant force among the O'Connors of Carbury and in north Connacht, in opposition to his cousin, Tadhg (qv) (d. 1371) son of Maghnus O'Connor (qv), who had the stronger claim to the lordship. The rivals defeated each other by turns, Tadhg overcoming Domhnall's forces in 1365, and Domhnall slaughtering Tadhg's galloglass troops at Ballysadare Strand the following year. But as Domhnall was unable completely to crush Tadhg's power base, the two came to terms in 1368, dividing Carbury equally between them. Later that year, however, Ruaidhrí O'Connor (qv), king of Connacht intervened, arresting Tadhg at Ardkillin, Co. Roscommon, and giving him into Domhnall's custody, who in 1371 executed him – an act that sparked great unrest throughout Connacht.

By 1385 Domhnall was an immensely powerful figure in north Connacht, and had formed an alliance with the O'Connor Ruadh branch of the dynasty. In that year he burned the lands of the MacDermotts and exacted a terrible revenge upon the MacWilliam Burkes and the Barretts for their incursions into southern Sligo, utterly destroying their lands in Tirawley in Mayo. In 1386, at the head of a confederation of O'Haras, O'Dowds, and MacDonaghs, he attacked the Barretts again. In 1388 his power was such that he could turn his attention to Donegal and Roscommon. His son Muircheartach Bacach O'Connor (d. 1403), the offspring of his union with Méadhbh O'Rourke, won a victory over the O'Donnells at Assaroe in that year, but Toirdhealbhach an Fhíona O'Donnell (qv), lord of Donegal, invaded Sligo and forced Domhnall to submit. After skirmishes against the O'Rourkes, Domhnall formed an alliance with them and the MacDonaghs in 1389, which allowed him to concentrate on his conflict with the O'Donnells; in that year he burned southern Donegal and in 1390 he levelled the castle at Kilbarron and sought an alliance with the O'Neills of Tyrone against the O'Donnells. In 1392 he and Niall Mór O'Neill (qv) led two separate armies into Donegal in a pincer movement against Toirdhealbhach an Fhíona; but the O'Donnells managed to prevent the armies from linking up and isolated Domhnall's force at Kinnaweer just north of Kilmacrenan, attacked, and routed them, forcing Domhnall to flee for the safety of Sligo. This defeat launched a brief period of decline for the O'Connor Sligo dynasty, which lasted beyond Domhnall's death on 18 December 1395.

Domhnall was succeeded by Muircheartach Bacach, who continued to prosecute the struggle against the O'Donnells on Sligo's northern frontier. In 1397 he defeated the O'Donnells and his dynastic rivals, the sons of Cathal Óg, in a pitched battle at Lissadell in Sligo, but in 1398 was routed at Ballyshannon by the O'Donnell clients the O'Durneens. Soon afterwards he gave his support to the O'Connor Don faction in their struggle against their bitter enemies the O'Connor Ruadh. After a campaign throughout Connacht in support of his allies, Muircheartach Bacach fell ill and died at Sligo castle on 29 September 1403. He was succeeded by his half-brother Brian O'Connor (c.1360–1440), the son of Domhnall's second wife, Raghnailt O'Donnell, who was to prove a powerful and influential figure and played an important role in O'Connor and Connacht politics. In 1406 he acted as inaugurator during the installation at Carnfree of Cathal O'Connor Don (qv), son of Ruaidhrí, as king of Connacht. After Cathal's defeat and capture in 1407, Brian remained a steadfast supporter of his cause, and in 1409 braved the O'Connor Ruadh and O'Kelly siege of Roscommon castle to resupply the beleaguered O'Connor Don garrison.

With his brothers Eoghan (d. 1444) and Toirdhealbhach Carrach (d. 1455), Brian continued to consolidate and expand the power of the Carbury O'Connor dynasty by frequently raiding Mayo, Roscommon, and Donegal. Occasionally this drive met with defeat, as in 1416 when Toirdhealbhach Carrach was overcome by Meiler d'Exeter, but generally Brian's campaigns were successful, and in that year the O'Donnells decided to make peace. By 1419 Brian had formed an alliance with Domhnall O'Neill (qv), king of Tyrone, and while the O'Donnells were campaigning in Tyrone he came to his ally's aid by burning much of Donegal. His growing confidence was demonstrated in 1420 by the building of a castle at Bundrowes to protect his northern frontier, where Eoghan and Toirdhealbhach Carrach inflicted a humiliating defeat on the O'Donnells when they approached to attack the new fortification; in the rout Niall Garbh O'Donnell (qv), the future king of Tyrconnell, was forced to swim for his life to a merchant ship in Assaroe Bay. In the same year Brian's regional position was underscored when Domhnall O'Neill sought sanctuary in Sligo after being expelled by his rival Eóghan O'Neill (qv).

The power of Brian's dynasty ensured a long period of peace until 1432, in which year Brian and his brothers sealed an alliance with Eóghan O'Neill. In 1434, during a feud between Niall Garbh O'Donnell and his brother Neachtan O'Donnell (qv), Sligo became a safe haven for Neachtan, with whom Brian plundered much of southern Donegal and fended off revenge raids led by Niall Garbh's sons. The peace was restored to north-west Ireland after Niall Garbh's capture by the English in 1435, which left Brian as the most powerful Irish lord in the region, a role he again displayed when in 1439 he proclaimed Aodh O'Connor Don (qv) king of Connacht in opposition to Tadhg O'Connor Ruadh (qv). After an impressive and successful reign of thirty-seven years, Brian died in 1440 and was succeeded by his brother Eoghan, who was killed in 1444 by the sons of Cormac MacDonagh. The succession then passed to Toirdhealbhach Carrach who encountered considerable opposition from his nephews, the sons of Eoghan; in an act of outright rebellion, in 1445 they joined Neachtan O'Donnell, now lord of Donegal, and Philip Maguire to burn Sligo. Although the tensions simmered below the surface, Toirdhealbhach Carrach apparently managed to maintain control of his lordship until his death in 1455.