Leopold Kronecker

Leopold Kronecker (7 December 1823 Liegnitz, Prussia - 29 December 1891) was a German mathematician of Jewish descent.
At first he was a business man and earned a lot of money. Then he devoted himself to mathematics. He is famous for his work on number theory, determinant and algebra. He criticized Cantor's work on set theory. He was a pupil and lifelong friend of Ernst Kummer.