Castlereagh and Canning duel on Putney Heath

Background. Viscount Castlereagh served as Secretary of State for War and the Colonies in the ministry of the Duke of Portland, while George Canning served as Foreign Secretary. Their relationship deteriorated due to differing opinions on the conduct of the war against Napoleonic France in 1808 and 1809. These disagreements led to Canning demanding a new appointment to the War Office in spring 1809, accompanied by a threat of resignation.

Conflict. Canning's demand for a new appointment and threat of resignation were discussed with various Cabinet members and King George III without Castlereagh's knowledge. Castlereagh only became aware of these discussions in the late summer of 1809. On 19 September 1809, he sent Canning a nine-page letter accusing him of violating the principle of good faith, both privately and publicly, before challenging him to a duel.

Aftermath. The duel took place at 6 a.m. on 21 September 1809 at Putney Heath on Lord Yarmouth's estate. Castlereagh wounded Canning in the thigh. Following the duel, Castlereagh was obliged to resign. On 3 October 1809, he published a vindication that shifted public opinion, portraying him as the victim of a conspiracy by Cabinet colleagues who had secretly plotted against him.