Part II. History of Thomond
Chapter 13. History of Thomond before it was formed into an English county: From the Death of De Clare in 1318 to the Formation of Thomond into an English County in 1580

Death of Donogh, second Earl, and appointment by the people to the chieftaincy of Thomond of his half brother Donald

Murrogh O’Brien died in 1551, and the earldom devolved upon his nephew, Donogh the Fat, according to the terms of its creation. He was, however, to be earl only for his lifetime, without power to transmit the title to his descendants. To enable him to do that, he was advised to surrender his dignities to Edward VI., and to apply for a new patent. The young king did all that he wanted and more; he granted to Donogh the lands and hereditaments which had lapsed to the Crown by the death of Murrogh, to descend to his heirs according to the course of the common law of England. The new patent bears date the 7th of November, 1552. No sooner were its terms made known than the half brothers of Donogh (who were the children of his father by his second marriage with the daughter of the Earl of Desmond), saw how completely their interests had been sacrificed. Instead of having a share in the inheritance of their father, and having the right of being nominated Tanists in case that, at any time, one or other of them might, perchance, be selected for that honour by the Dalcassians, they saw themselves cut off from every hope of succession to lands or attainment of dignity. They flew to arms and attacked their brother, in the dead of night, at the Castle of Clonroad, whither he had retired for safety. They burned and plundered the town, but whether they reached Donogh is not related, although his death happening five weeks afterwards gave rise to the suspicion that he received some bodily injury at the hands of his infuriated brothers. ^[18] Being thus delivered from their foe, they proceeded to elect a King of Thomond according to the ancient usage of the country, and so set at naught the validity of the title of earl inherited by their nephew, Conor. The choice of the people fell upon the eldest of the brothers, whose name was Donald, and who was the ancestor of the O’Briens of Ennistymon. He was evidently a man worthy of their vote, for he was bold and warlike, as the relation of his actions will sufficiently show. He invaded Ely O’Carroll, and compelled its chieftains to submit to his authority. He ravaged the territory of Clanrickard. He invested the Castle of Doonmulvihil, inhabited then by the earl, but was forced to raise the siege. He immediately afterwards invaded Clanrickard, and thence drove away flocks and herds belonging to the Burkes. ^[19] In 1555 he led an army into Leinster to oppose the forces of the Lord Deputy Sussex. He met them in the Queen’s County, and a truce was concluded, both parties preferring a patched-up peace to the risk of a battle. In this truce O’Brien acted as the representative of all the Irish from the Barrow to the Shannon. ^[20]