Aghakilmore’s Field of Defeat
Archived: 20 October 2026
Abstract
The best-documented Irish event of 1429 was a major defeat at Achadh Cille Móire, now generally identified with Aghakilmore in County Cavan. It was not a battle between two neatly bounded nations. Rather, it grew from the shifting alliances, rival branches and armed followings that shaped lordship in the Breifne borderlands. The annals place it firmly in this year, while their differing emphases also reveal why a single encounter could matter far beyond the field on which it was fought. War in Breifne The Annals of Ulster report a “great war” between Tadhg Ua Ruairc (O’Rourke) and Eóghan Ua Raighillaigh