Who was the first British king called George to be born in Britain?

George III (George William Frederick; 4 June 1738 – 29 January 1820) was King of Great Britain and 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 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.

George was born on 4 June 1738 in London at Norfolk House in St James's Square. He was a grandson of King George II, and the eldest son of Frederick, Prince of Wales, and Augusta of Saxe-Gotha. As he was born two months prematurely and thought unlikely to survive, he was baptised the same day by Thomas Secker, who was both Rector of St James's and Bishop of Oxford.