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.

George III was King of Great Britain and Ireland from 25 October 1760 until his death in 1820. The Acts of Union 1800 unified Great Britain and Ireland into the United Kingdom of Great Britain and Ireland, with George as its king. He was concurrently Duke and Prince-elector of Hanover in the Holy Roman Empire before becoming King of Hanover on 12 October 1814. He was a monarch of the House of Hanover, who, unlike his two predecessors, was born in Great Britain, spoke English as his first language, and never visited Hanover.