Karl Weierstrass
Karl Theodor Wilhelm Weierstrass (; German: Weierstraß [ˈvaɪɐʃtʁaːs]; 31 October 1815 – 19 February 1897) was a German mathematician often cited as the "father of modern analysis". Despite leaving university without a degree, he studied mathematics and trained as a school teacher, eventually teaching mathematics, physics, botany and gymnastics.