DIED A. D. 1271.
From The Irish Nation: Its History and Its Biography
By James and Freeman Wills
OF Walter de Burgo we have little to offer. He succeeded his father last noticed. By his marriage with the heiress of De Lacy, he acquired the earldom of Ulster.
It happened that the Macarthys in the south having taken arms against the Desmonds, and gained a victory, were in the pursuit of their success led to some encroachment on the right of Earl Walter. He attacked the Irish chief and gave him a signal defeat; and followed it up by an inroad into their country, and after spreading devastation, compelled the Macarthys to give hostages. This victory enabled the Geraldines to lift their heads again. De Burgo, whose interests were those of a rival, did not acquiesce in such a result, and a long and deadly feud ensued.
In the course of this the Geraldines, resenting the supposed partiality of the Lord Deputy's interference, seized his person and sent him prisoner to one of their castles, thus drawing upon themselves a more formidable hostility. De Burgo pushed his advantage into Connaught, until he roused the resentment of Aedh O'Conor, the successor of Feidlim, who collected his forces and gave him a sanguinary defeat.
His death followed soon after at his castle in Galway.