George III (George William Frederick; 4 June 1738 – 29 January 1820) was King of Great Britain and of Ireland from 25 October 1760 until the union of the two kingdoms on 1 January 1801, after which he was King of the United Kingdom of Great Britain and Ireland until his death in 1820. He was the longest-lived and longest-reigning king in British history. He was concurrently Duke and Prince-elector of Brunswick-Lüneburg ("Hanover") in the Holy Roman Empire before becoming King of Hanover on 12 October 1814. He was a monarch of the House of Hanover but, unlike his two predecessors, he was born in Great Britain, spoke English as his first language and never visited Hanover.