On September 21, 1899, Juliusz Paweł Schauder was born in Lemberg (Austro-Hungarian Empire, today Lviv, Ukraine). In 1934, he extended Brouwer’s topological notion of mapping degree to Banach spaces. By 1930, he had generalized a theorem of Banach’s, now known as the Schauder fixed-point theorem. Schauder was murdered by the German Gestapo in 1943 in Lemberg. More information can be found here.