Which son of Sophia of Hanover ruled part of the Holy Roman Empire?
George I of Great Britain George I (George Louis; German: "Georg Ludwig" ; 28 May 1660 – 11 June 1727) was King of Great Britain and Ireland from 1 August 1714 until his death, and ruler of the Duchy and Electorate of Brunswick-Lüneburg (Hanover) in the Holy Roman Empire from 1698.
Frederick William I of Prussia Frederick William I (German: "Friedrich Wilhelm I" ) (14 August 1688 – 31 May 1740), known as the 'Soldier King,' was the King in Prussia and Elector of Brandenburg from 1713 until his death, as well as the father of Frederick the Great. He was in personal union the sovereign prince of the principality of Neuchâtel.