Dobhar in north-central Donegal: The territory around Kilmacrenan. They derive their clan-name from their ancestor Dalach, Lord of Tir-conaill, who died in 868, and who was the first of their immediate ancestors to become Lord of Tir-conaill, a dignity continued by his son Eigheachan, father of their eponymous ancestor Domhnall. They did not, however, again become chiefs of the Cineal Conaill until the thirteenth century, when they rose on the downfall of some of their Cineal Conaill kinsmen, the O’Canannains or O’Cannons (O Canannain) and O’Muldorys or O’Mulderrys (O Maoldoraidh). Both of these families are now very rare.

Afterwards the O’Donnells established themselves as the ruling family of the Cineal Conaill and all Donegal, and continued as such for centuries, until the final submergence of the Gaelic order in the seventeenth century. The O’Donnells, as princes of Donegal, were consistently one of the most able families in the Gaelic aristocracy, and not only successfully defended their territory against both the English and native adversaries alike, but they also made their power respected throughout the north and west of Ireland. Their most famous chief was Hugh Roe (Red Hugh) O’Donnell, who escaped his treacherous imprisonment by the English at Dublin Castle (he was rescued, after his bold escape, by The O’Hagan, and with the assistance of the Wicklow clans) and later fought at Kinsale. Rory O’Donnell was with The O’Neill in the Flight of the Earls at the beginning of the seventeenth century, while other famous O’Donnells distinguish the pages of Irish and Continental history during the seventeenth and eighteenth centuries. A branch of the family (descended from Shane Luirg, son of Turlough O’Donnell of the Wine, Lord of Tir-conaill in the early fifteenth century) became established in Limerick and Tipperary.

The O’Friels (O Firghil) descend from Eoghan, nephew of Sedna, ancestor of the Clann Dalaigh, and brother of the illustrious and sanctified prince of the Cineal Conaill who established Iona in the sixth century: St. Columba (also known as St. Columcille—see Chapter IV). The O’Friels were hereditary abbots (erenaghs) of Kilmacrenan in the old Clann Dalaigh country in Donegal. The O’Freil had the privilege of inaugurating The O’Donnell as chief of the Cineal Conaill and lord of Tirconnell (Tir-Conaill).