 He was also made a colonel of foot in the Irish army and upheld the Royalist cause against Cromwell.In 1650 he was governor of Nenagh castle for his brother in law, James Butler, at that time the 12th Earl of Ormond, leader of the royalists.At the end of 1650 he defended the castle against the Parliamentarian army under Henry Ireton, which attacked it on the way from the siege of Limerick back to their winter quarters at Kilkenny.