The German mathematician Karl Weierstrass made fundamental contributions in the foundations analysis, and specifically in the following areas:
Weierstrass studied finance in college, as his father wished, but was a rather desultory student and never completed his degree. He was largely self-taught in mathematics. He taught secondary school until his fame as a mathematician was established. Afterwards, Weierstrass taught at the University of Berlin, where he exerted a profound influence on many of his students, who would later become important mathematicians.