During the Monmouth Rebellion, it fought at Sedgemoor in July 1685; at the November 1688 Glorious Revolution, Trelawny and half the regiment deserted to William III. He was briefly replaced by the loyalist Charles Orby, then reinstated when James went into exile. From 1690 to 1691, it served in the Williamite War in Ireland, including the Battle of the Boyne and sieges of Cork and Limerick. When the war ended with the October 1691 Treaty of Limerick, it returned to England.