George was the eldest son of Ernest, Duke of Brunswick-Luneburg, Elector of Hanover in Germany, and his wife Sophia. He was born on 28th May (or 7th June in New Style dating) 1660 and succeeded his father as Elector. By the terms of the Act of Settlement he succeeded his second cousin Queen Anne (who had no surviving children) on the British throne on 1st August 1714. During his reign the Jacobite rising in Scotland, in favour of the son of James II, was put down.
His married his first cousin Sophia at Celle on 22nd November 1682. The marriage was dissolved in 1694.
George I was crowned on 20th October 1714. He could not speak very much English and the ceremonies had to be conducted mostly in Latin as his ministers could not speak German.
He died on 22nd June 1727 while on a visit to Germany and was buried in Hanover. In 1957 his coffin was moved to the mausoleum at Herrenhausen.
Oxford Dictionary of National Biography 2004
George I, Elector and King by Ragnhild Hatton, 1978
Godfrey Kneller [Public domain], via Wikimedia Commons