
Robert Stewart, 2nd Marquess of Londonderry, KG, GCH, PC, PC (Ire), Anglo-Irish politician and statesman usually known as Lord Castlereagh, derived from the courtesy title Viscount Castlereagh by which he is styled from 1796 to 1821, is born in Dublin on June 18, 1769. As secretary to the Viceroy of Ireland, he works to suppress the Irish Rebellion of 1798 and to secure passage in 1800 of the Irish Act of Union. As the Foreign Secretary of the United Kingdom from 1812, he is central to the management of the coalition that defeats Napoleon and is British plenipotentiary at the Congress of Vienna. In the post-war government of Lord Liverpool, he is seen to support harsh measures against agitation for reform.
Stewart is born in 28 Henry Street, in Dublin’s Northside. He is the second and only surviving child of Robert Stewart (the elder) and his wife Sarah Frances Seymour-Conway. His parents marry in 1766. He has recurring health problems throughout his childhood, and is sent to The Royal School, Armagh, rather than to England for his secondary education. At the encouragement of Charles Pratt, 1st Earl Camden, who takes a great interest in him and treats him as if he is a grandson by blood, he later attends St. John’s College, Cambridge (1786–87), where he applies himself with greater diligence than expected from an aristocrat and excels in his first-year examinations. But he then withdraws, pleading an illness that he admits to Camden is something “which cannot be directly acknowledged before women,” i.e. something sexually transmitted.
Early in his career in Ireland, and following a visit to revolutionary France, Stewart recoils from the democratic politics of his Presbyterian constituents in Ulster. Crossing the floor of the Irish House of Commons in support of the government, he takes a leading role in detaining members of the republican conspiracy, the United Irishmen, his former political associates among them. After the 1798 Rebellion, as Chief Secretary for Ireland, he pushes the Act of Union through the Irish Parliament. But it is without the Catholic Emancipation that both he and British Prime Minister William Pitt believe should have accompanied the creation of a United Kingdom.
From 1805 Stewart serves under Pitt and then the Duke of Portland as Secretary of State for War. In 1809 he is obliged to resign after fighting a duel with the Foreign Secretary, George Canning, in a dispute over the Walcheren Campaign. In 1812 he returns to government serving Lord Liverpool as Foreign Secretary and as Leader of the House of Commons.
Stewart organises and finances the alliance that defeats Napoleon, bringing the powers together at the Treaty of Chaumont in 1814. After Napoleon’s second abdication in 1815, he works with the European courts represented at the Congress of Vienna to frame the territorial, and broadly conservative, continental order that holds until mid-century. He blocks harsh terms against France believing that a treaty based on vengeance and retaliation will upset a necessary balance of powers. France is restored to the frontiers of 1791, and her British-occupied colonies are returned. In 1820 Stewart enunciates a policy of non-intervention, proposing that Britain hold herself aloof from continental affairs.
After 1815, at home, Stewart supports repressive measures that link him in public opinion to the Peterloo Massacre of 1819. Widely reviled in both Ireland and Great Britain, overworked, and personally distressed, he commits suicide on August 12, 1822. He is found in a dressing room seconds after he has cut his own throat using a small knife. He collapses and dies almost instantly.
(Pictured: “Robert Stewart, 2nd Marquess of Londonderry,” oil on canvas by Thomas Lawrence, National Portrait Gallery)





