From the above link...

Later, in 1543, the senior O'Byrne leaders petitioned the government to shire their territory. St Ledger, three years later, praised the effectiveness of the sheriff of O'Byrnes' Country. A force under Dowlyn McCahir Roe O'Byrne and another Callogh McBran served in Scotland during Henry VIII's 1544-1545 Scottish campaign. Callogh McBran was captain of the Irish kerne. This force quickly earned a reputation among the Scots for ferocity. For his services Callogh McBran was rewarded with the sum of £13 6s 8d in September 1545, before his repatriation. Their service in Scotland had much to do with Earl James's leadership of the Irish contingent. Further signs of their goodwill towards the government were evinced in 1546. Dowlyn O'Byrne appeared among a list of lords considered fit to serve Henry VIII in a fresh Scottish campaign. This period, through government campaigns and treaties, saw a decline in the power of Gaelic overlords, which facilitated the rise of the traditionally weaker septs in east Leinster.