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.
Otto IV, Holy Roman Emperor Otto IV (1175 – May 19, 1218) was one of two rival kings of Germany from 1198 on, sole king from 1208 on, and Holy Roman Emperor from 1209 until he was forced to abdicate in 1215. The only German king of the Welf dynasty, he incurred the wrath of Pope Innocent III and was excommunicated in 1210.