He also pursued his family’s interests at the expense of the towns of Galway and Athenry, two urban centres in Connacht which, despite their remoteness from the Pale, were notable for their loyalty to Crown government in Ireland.
Although both families were of Norman stock, the western de Burghs (or Burkes) were integrated into the Gaelic world, whereas the Fitzgeralds of the Pale, though Gaelicised, retained cultural, social and political links to England.
The King's Deputy, Gerald, Earl of Kildare (Gearóid Mór), became concerned that Ulick Burke's attempt to gain supremacy in Connacht could simultaneously threaten the Crown's interests in that province and his claim to be the paramount magnate in Ireland.
But Ulick Burke resisted all attempts to have his power subordinated by the Earl of Kildare, forming an alliance with O'Brien of Thomond and the magnates of Munster.
In 1503 Ulick Burke attacked and destroyed the castles of O'Kelly, Lord of Hymany, at Monivea (Muine Mheá), Garbally (Gallach) and Castleblakeney (Garbhdhoire).
[7] The armies met on the slopes of Knockdoe, almost a mile to the north of Lackagh Parish Church, with heavily armed Gallowglass playing a large part on both sides.
[5] The battle appears to have lasted all day, with the heaviest fighting (according to tradition) taking place along the River Clare in the townland of Ballybrone (Baile Bhróin).
His army remained the night on the field as a token of victory, then marched to Galway, looting Claregalway castle en route and taking as prisoners the two sons and daughter of Ulick Burke.