Donnell Óg O'Donnell

[2] Lasairfhíona's aunt, Beanmhidhe, daughter of Toirdhealbhach Ó Conchobhair, was wife to the Scottish lord, Maol Mhuire an Sparáin, son of Suibhne mac Duinnshléibhe, whose kindred would become very important to Domhnall Óg's career.

[3] Tír Chonaill, centred on modern County Donegal, emerged from a confederation of tribes called the Cenél Conaill, claiming descent from the legendary figure Conall Gulban.

Traditionally, leadership over Tír Chonaill alternated between rival branches of a sub-grouping known as the Cenél Aedha, which included the O'Muldory and O'Cannon families.

Maol Seachlainn died at the Battle of Ballyshannon in 1247 fighting against Maurice FitzGerald, 2nd Lord of Offaly, after which Ruaidhrí Ó Canannáin was installed as ruler of Tír Chonaill.

[12] Domhnall Óg's reign saw not only a halt to the expansion of Anglo-Norman rule in the north west, but also the emergence of Tír Chonaill as a serious contender with the O'Neill dynasty for supremacy in Ulster, and an important player in politics across Ireland.

The Annals of the Four Masters record the following military exploits of Domhnall Óg as king of Tír Chonaill: 1259: A successful retaliatory raid on Tyrone and Oriel.

But after Domhnall Óg, the balance of power within Tír Chonaill would be determined less by relations among the traditional septs of Cenél Conaill than by feuding within the O'Donnell dynasty and their Mac Suibhne vassals, often with direct support from one Scottish magnate or another.