Golo Mann, born Angelus Gottfried Thomas Mann, was a popular historian, essayist and writer. He was the third child of the novelist Thomas Mann and his wife Katia Mann. Golo Mann, originally a Bavarian German, held Czechoslovakian citizenship from 1936 on, American 1943–68, Swiss from 1968 on and additionally German since 1976.

https://en.wikipedia.org/wiki/Golo_Mann