Prince Augustus Frederick, Duke of Sussex, was the sixth son and ninth child of King George III and his queen consort, Charlotte of Mecklenburg-Strelitz. He was the only surviving son of George III who did not pursue an army or navy career. A Whig, he was known for his liberal views, which included reform of Parliament, abolition of the slave trade, Catholic Emancipation, and the removal of existing civil restrictions on Jews and Dissenters.

Charlotte of Mecklenburg-Strelitz was Queen of Great Britain and Ireland as the wife of King George III from their marriage on 8 September 1761 until her death in 1818. The Acts of Union 1800 unified Great Britain and Ireland into the United Kingdom of Great Britain and Ireland. As George's wife, she was also Electress of Hanover until becoming Queen of Hanover on 12 October 1814. Charlotte was Britain's longest-serving queen consort, serving for 57 years and 70 days.