The name of Maurice, the third Baron of Offally, and uncle of John, the first Earl of Kildare, draws our attention naturally to the last enterprise of his life—the attempt to establish his son-in-law, Thomas de Clare, in possession of Thomond. The de Clares, Earls of Gloucester, pretended a grant from Henry II. of the whole of Thomond, as their title to invade that principality; but their real grant was bestowed by Edward I., in the year 1275. The state of the renowned patrimony of Brian had long seemed to invite such an aggression. Murtogh, son of Donnell More, who succeeded his father in 1194, had early signalized himself by capturing the castles of Birr, Kinnetty, Ballyroane and Lothra, in Leix, and razing them to the ground. But these castles were reconstructed in 1213, when the feuds between the rival O'Briens—Murtogh and Donogh Cairbre—had paralyzed the defence force of Thomond. It was, doubtless, in the true divide-and-conquer spirit, that Henry the Third's advisers confirmed to Donogh the lordship of Thomond in 1220, leaving to his elder brother the comparatively barren title of King of Munster. Both brothers, by alternately working on their hopes and fears, were thus for many years kept in a state of dependence on the foreigner. One gleam of patriotic virtue illumines the annals of the house of O'Brien, during the first forty years of the century—when, in the year 1225, Donogh Cairbre assisted Felim O'Conor to resist the Anglo-Norman army, then pouring over Connaught, in the quarrel of de Burgh. Conor, the son of Donogh, who succeeded his father in the year 1242, animated by the example of his cotemporaries, made successful war against the invaders of his Province, more especially in the year 1257, and the next year; attended with O'Conor the meeting at Beleek, on the Erne, where Brian O'Neil was acknowledged, by both the Munster and the Connaught Prince, as _Ard-Righ_. The untimely end of this attempt at national union will be hereafter related; meantime, we proceed to mention that, in 1260, the Lord of Thomond defeated the Geraldines and their Welsh auxiliaries, at Kilbarran, in Clare. He was succeeded the following season by his son, Brian Roe, in whose time Thomas de Clare again put to the test of battle his pretensions to the lordship of Thomond.