Tir Ollíol

Irish: Tír Ollíol a territory in modern Co. Sligo now represented by the barony of Tirerril in southeast Co. Sligo.

This territory is named after Olliol (Ailill) one of the sons of Eochaid Mugmedon and half brother of Niall of the Nine Hostages, from whom descended the Uí Ailello. The Uí Aillelo dynasty sank into obscurity at an early date. but the name is preserved as the tuath of Tir Ollíol (Tirerril).

The Lords of Tir Olioll were Mac Donnchadha of the Uí Briúin Aí a branch of the Mac Díarmada of Moylurg (Magh Luirg). The Mac Donagh (Mac Donnchadha) surname originates from Donnchadh, son of Tomaltach na cairge (of the rock) ua Mac Diarmata, who was King of Moylurg 1197-1207. They later split into two groups, one based in Collooney and Ballindoon (Tirerril), and the other in Ballymote (Corran).

Saint Patrick departed across the mountain of the sons of Ailellus, and he founded churches there, Taemnach, and Ethenach, and Cell Angle, and Cell Senchuoe. AD 545.2 St. Ailbhe, of Seanchu Ua nOiliolla, died.

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