MP [I] 1790 – 1800.
Keeper of the privy seal [I] July 1797–1801; ld. of treasury [I] 1797 – 1804; chief sec. to ld. lt. [I] Mar.-Nov. 1798 (ad. int.), 1798–1801; PC [I] 20 Oct. 1797, [GB] 19 Dec. 1798; pres. Board of Control July 1802 – Feb. 1806; sec. of state for War and Colonies July 1805 – Feb. 1806, Mar. 1807 – Nov. 1809; sec. of state for Foreign affairs Feb. 1812 – d.; plenip. at Paris 1814, 1815, Vienna 1814 – 15, Aachen 1818.
Lt.-col. co. Londonderry militia 1793, col. 1798 – d.; gov. co. Londonderry 1805; custos rot. 1821.
The latest biography is by Wendy Hindle (1981). For his early career see also H. M. Hyde, Rise of Castlereagh (1933) and Ione Leigh, Castlereagh (1951); for his career at the India Office, J. A. R. Marriott, Castlereagh: a pol. biog. (1936), ch. 7; for his diplomatic career, Sir C. K. Webster, Foreign Policy of Castlereagh 1812-1815, 1815-1822; H. A. Kissinger, A World Restored, 1957. A synthesis was attempted by C. J. Bartlett, Castlereagh (1966). Much of his official corresp. appeared in his half-bro.’s Mems. and Corresp. Visct. Castlereagh (12 vols. 1848-53) and some of his private corresp. in Lady Londonderry’s Robert Stewart, Visct. Castlereagh (1904).
STEWART, Hon. Robert (1769-1822)
