O'Donnell of Tirconnell

Major dynasty of Irish Gaelic chiefs in northwest Ulster (modern County Donegal); a significant power in Ireland from the mid-13th to early 17th centuries.

The O'Donnells rose to prominence through their successful resistance both to the Anglo-Norman colonists, who had penetrated deep into Ulster in the 13th century, and the O'Neills, the ascendant family in Ulster. Strong lines of succession coupled with shrewd alliances with gallowglass families such as the MacSweeneys, descendents of Scottish mercenary troops imported by the Irish chiefs in the 13th century, allowed them to exercise control over a large portion of north Connacht (now counties Sligo and Mayo) during the late 15th and early 16th centuries. The family even gained brief dominance over the O'Neills under Aodh Ruadh O'Donnell (1461–1505). The height of O'Donnell achievements was reached under Manus O'Donnell (1535–1563) who extended their claims in Connacht, supplanted the O'Neills as the ally of the Kildare Fitzgeralds, and was a generous patron of the arts.

Manus O'Donnell's deposition by his son Calvach in 1555, coupled with fierce invasions by Shane O'Neill (c. 1530–1567), severely weakened the dynasty. Calvach was granted the title Earl of Tyrconnell by the English crown, but died before receiving the royal charter. Aodh Dubh O'Donnell (chief 1566–93) attempted to shore up the O'Donnell's position by marriage alliances and careful diplomacy with the English government. However, on his death ‘Red Hugh’ (Aodh Ruadh) O'Donnell (chief 1593–1602), Aodh Dubh's son by his Scots wife Fionualla MacDonnell, seized power and, with Hugh O'Neill, 2nd Earl of Tyrone, led the O'Donnells into war against the crown in 1593. Following the defeat of the Ulster army at Kinsale in 1601, Hugh O'Donnell went to Spain seeking further support and died (possibly by poisoning).

After the surrender of the Ulster rebels in 1603, Hugh's brother Rory was created Earl of Tyrconnell, but he joined with Hugh O'Neill and other Ulster lords in the Flight of the Earls from Ireland in 1607. In the aftermath the family's title was suppressed and their lands confiscated, destroying their power base.