The title "King of Hanover" refers to the monarchs who ruled the Kingdom of Hanover, a German state that existed from 1814 to 1866. The kingdom was established after the Congress of Vienna and was ruled by the British royal family, specifically the House of Hanover. The last king was George V of Hanover, who lost his throne when Hanover was annexed by Prussia. The Kingdom of Hanover was significant in European history due to its connection with the British monarchy. The Hanoverian dynasty began with George I of Great Britain, who became king in 1714. The union of the British and Hanoverian crowns lasted until the loss of the Hanoverian throne in 1866, marking a notable period in both British and German history.