Burke (de Burgh), Thomas (d. 1402), 2nd lord of Lower Connacht, second son of Sir Edmond Albanach (qv), succeeded to the title of MacWilliam Burke on his father's death (1375). His succession marked a departure from primogeniture, because it passed over a son of Thomas's elder brother, William, who had died of smallpox in 1368. While his succession to the lordship was uncontested, Thomas was never able to exert the same control over the lordships of Connacht that his father had exercised.
The decade 1376–86 was marked by two major and intertwined events that permanently altered the politics of Connacht. Thomas failed to subdue the O'Connors, losing in battle to Ruaidhrí O’Connor (qv) at Roscommon in 1377, but he did assert his power over the Clanricard Burkes of Galway in 1380. However, the death of Ruaidhrí (1384) saw the O'Connor lordship divide into two warring segments, Ó Conchobhair Ruadh and Ó Conchobhair Donn. Thomas tended to support Toirdhealbhach Ruadh O'Connnor in the ‘general warfare’ that erupted. One significant effect of the warfare was the increased independence of the Clanricard Burkes of Upper Connacht (Galway), a fact that Thomas accepted in 1386 when he recognised Richard Óg (qv) of the Clanricard Burkes as the senior MacWilliam by right of prior posession of a lordship.
Thomas regained the position of senior Burke on Richard Óg's death (1387), and afterwards was generally regarded as the most powerful of the Anglo-Irish of Connacht, a fact underlined by his appointment as guardian or custos of Connacht by the Dublin administration (December 1388). This was a legal fiction to hide his virtual independence from Dublin's control, but it was an important one. Clearly, Thomas continued to regard himself as a loyal subject of the king, and submitted himself to Richard II (qv) when the king came to Ireland in the winter of 1394–5. For the five years prior to his death in 1402, Thomas worked to secure his shrunken lordship, using his alliance with Toirdhealbhach Ruadh O'Connor to subdue their rival, Ó Conchobhair Donn. The final result of these raids was that, while he failed to reestablish his control over Galway, Thomas did secure a stable lordship in north-west Connacht that remained virtually unchanged in area till the middle of the sixteenth century.