Of Lord Iveagh's Regiment the names of the colonel, the first and second lieutenant-colonels, a captain, no lieutenants, and an ensign are recorded. No details of companies or men are forthcoming.
Bryan Magennis, Lord Iveagh, was involved in the troubles of the 1641 rebellion and was outlawed in 1642. He sat in the Parliament of 1689 and his outlawry was then reversed. He was appointed lord-lieutenant of Down, and two other Magennises were his deputy-lieutenants. Lord Iveagh and his sept furnished James with two regiments, one of dragoons, and the other of infantry. At the end of the war he entered the Austrian service with a choice battalion of 500 men. He married Lady Margaret de Burgh, daughter of William, seventh Earl of Clanricarde. In July 1690 he held Drogheda with a garrison of 1,300 men, but he surrendered the town on condition that his men were not made prisoners of war. Lord Iveagh was among the negotiators of the Articles of Limerick. William III hoped that the departing Irish would take service with Leopold, and this peer was one of the few who did so. He reached Hungary for service against the Turks, but he and his regiment died of plague ( C.S.P., Dom., 1691/2, January 9, 1692, 91, 136; S.P. Ireland, King's Letter Book, i. 281, 295).