Viscount Castlereagh
1769-1822. British Tory politician. As chief
secretary for Ireland 1797-1801, he
suppressed the rebellion of 1798 and helped
the younger Pitt secure the union of England,
Scotland, and Ireland in 1801. As foreign
secretary 1812-22 he coordinated European
opposition to Napoleon and represented
Britain at the Congress of Vienna 1814-15.
When his father, an Ulster landowner, was
made an earl in 1796, he took the courtesy
title of Viscount Castlereagh. In 1821 he
succeeded his father as Marquess of
Londonderry. He sat in the Irish House of
Commons from 1790. In Parliament he was war
secretary 1805-06 and 1807-09, when he had to
resign after a duel with foreign secretary
George Canning. Castlereagh was foreign
secretary from 1812, when he devoted himself
to the overthrow of Napoleon and subsequently
to the Congress of Vienna and the congress
system. Abroad his policy favoured the
development of material liberalism, but at
home he repressed the Reform movement, and
popular opinion held him responsible for the
Peterloo massacre of peaceful demonstrators
in 1819.