The Kingdom of Hanover was established in October 1814 by the Congress of Vienna, with the restoration of George III to his Hanoverian territories after the Napoleonic era. It succeeded the former Electorate of Hanover, and joined 38 other sovereign states in the German Confederation in June 1815. The kingdom was ruled by the House of Hanover, a cadet branch of the House of Welf, in personal union with Great Britain between 1714 and 1837. Since its monarch resided in London, a viceroy, usually a younger member of the British royal family, handled the administration of the Kingdom of Hanover.

The Congress of Vienna of 1814–1815 was a series of international diplomatic meetings to discuss and agree upon a possible new layout of the European political and constitutional order after the downfall of the French Emperor Napoleon Bonaparte. Participants were representatives of all European powers and other stakeholders. The Congress was chaired by Austrian statesman Klemens von Metternich, and was held in Vienna from September 1814 to June 1815.