After the peace of 1646, concluded with the Marquis of Ormond, the king’s lord-lieutenant, but which shortly fell through, Lord Castlehaven retired to France, and served as a volunteer under Prince Rupert at the siege of Landrecies. Then, returning to Paris, he remained in attendance on the Queen of England and the Prince of Wales (Charles II.) at St. Germain till 1648. In that year he returned to Ireland with the lord-lieutenant, the Marquis of Ormond, and served the royal cause in that kingdom against the parliamentary forces under Ireton and Cromwell. The battle of Worcester being lost, and Cromwell the undisputed master of the three kingdoms, Castlehaven again followed the clouded fortunes of Charles II. to France. There he obtained permission to join the Great Condé. In the campaigns under that prince he had the command of eight or nine regiments of Irish troops, making altogether a force of 5,000 men. Thus we find the Irish refugees already consolidated into a brigade some years before the Treaty of Limerick expatriated those soldiers whose valor is more commonly identified with that title. Lord Castlehaven returned to England at the Restoration. In the war with Holland he served as a volunteer in some of the naval engagements. In 1667, the French having invaded Flanders, he was ordered there with 2,400 men to recruit the “Old English Regiment,” of which he was made colonel. The peace of Aix-la-Chapelle ended this war. Peace reigned in the Low Countries till the breaking out, in 1673, of the long and bloody contest between the Prince of Orange and the confederate Spaniards and Imperialists on the one side, and Louis XIV. on the other. This was the age of grand campaigns, conducted upon principles of mathematical precision by the great captains formed in the school of M. Turenne, before the “little Marquis of Brandenburg”[7] and the “Corsican corporal” in turn revolutionized the art of war. Castlehaven entered the Spanish service, and shared the checkered but generally disastrous fortunes of the Duke of Villahermosa and the Prince of Orange (William III.) against Condé and Luxembourg, till the peace of Nymegen put an end to the war in 1678.