Part II. History of Thomond
Chapter 12. History of Thomond before it was formed into an English county: From the earliest times, to the death of De Clare, and expulsion of the English in 1318.

De Clare collects his partisans and fights the people of Thomond at Dysert O’Dea; Defeat and death of de Clare

A.D. 1318. De Clare called together his partisans, English and Irish, the latter under the command of Brian Bane, who was almost the only person of his race that escaped death at Corcomroe. They decided to invade Ui Fearmaic, and to attack O’Dea in the first instance. The two brothers, Murrogh and Dermot O’Brien, resolved to support him, and with that object in view, drew their forces together at Dysert O’Dea. De Clare made a division of his troops into three bodies: the first he posted at Tulla O’Dea, under command of his son, with instructions to intercept the O’Connors, who were expected to come from Ennistymon. His second detachment was to march from the Fergus to Magowna. The third, under his own leadership, he brought to Dysert. When he arrived there (May 10^th, 1318) he found O’Dea posted in defence of a small stream that descends from the hills and falls into the neighbouring lake. The O’Deas opened their ranks on his approach, and he, mistaking that movement for a sign of fear, rushed onwards without thinking of consequences, and thus separated himself from the main body of his supporters. The Dal Cais closed in upon his troops, overwhelmed, and cut them to pieces, he himself being killed by the axe of Conor O’Dea. His son shared the same fate, being slain by Felim O’Connor, as that chieftain was rushing down with his followers from the neighbouring hill of Scamhall to support O’Dea. At that moment, Loghlen O’Hehir, with the men of Ui Cormaic coming up, the united forces of the Irish fiercely attacked the foreigners, and these being already dispirited by the loss of their leaders, gave way on all quarters, and a total rout ensued. Never was victory more decisive. ^[48] Its effect was to rid the country of Thomond for more than two centuries of everything Saxon.

Death of De Clare.
De Clare’s widow, hearing of the loss of her husband and son, set fire to the castle of Bunratty, and with what remained of her followers made sail for England, never to put her foot on Irish ground again. After this time, the name of de Clare disappears from the page of the history of Ireland. ^[49]