CASTLEREAGH, kas'el-ra, Robert Stew art, VISCOUNT, English statesman: b. 18 June 1769; d. 12 Aug. 1822. He was educated at Armagh and at Saint John's College, Cam bridge. He entered the Irish Parliament in 1790, became Viscount Castlereagh (1796). He turned Tory in 1795 and next year became keeper of the privy seal, but he continued a steadfast supporter of Catholic emancipation. Still, he believed that emancipation with an independent Irish Parliament would mean sim ply a transference of tyranny from the Prot estant oligarchy to a Catholic democracy; hence, as chief secretary from 1797, he bent his whole energies to forwarding Pitt's meas ure of union. Transferred by the union from Dublin to Westminster, he accepted office in the Addington ministry (1802), as president of the board of control; but the true second era in his career was as War Minister under Pitt from July 1805 to January 1806, and again under Portland from April 1807 to September 1809. His real greatness begins with March 1812, when, as Foreign Secretary under Lord Liverpool, he became the soul of the coalition against Napoleon, which, during the momentous campaigns of 1813-14, was kept together by him, and by him alone. He represented Eng
land at the congresses of Chatillon and Vienna in 1814-15, at the Treaty of Paris in 1815, at the Congress of Aix-la-Chapelle in 1818. As the leader of the Liverpool government in the lower house, he carried the suspension of the Habeas Corpus Act in 1817. The °Six Acts* of 1819 made him extremely unpopular. The retirement of Canning from the ministry (1820) threw the whole weight of business on Castlereagh. By the death of his father in 1821 he became Marquis of Londonderry. He was preparing to start for a congress at i Verona, when, in a fit of insanity, he commit ted suicide with a pen-knife at Foots Cray, his Kentish seat. Consult his (Memoirs and Correspondence' (12 vols., London 1848-53) and Hassall, Arthur, 'Viscount Castlereagh' (ib. 1908).