Gauss and Sophie Germaine
Gauss was from Brunswick, now Germany. His king and academic sponsor was killed by Napoleon Army. Gauss had a French pen-friend “Mr. Brun” who was the famous French lady mathematician Sophie Germaine in disguise. She asked Napolean’s general not to kill Gauss. He spent remaining life in the University of Göttingen, which produced Klein, Hilbert, Riemann… Göttingen replaced Paris to be the World Center of Math until Hitler destroyed it.