Karl Zsigmondy (Hungarian pronunciation: [ˈʒiɡmondi]) (27 March 1867 – 14 October 1925) was an Austrian mathematician of Hungarian ethnicity. He was a son of Adolf Zsigmondy from Pozsony, Kingdom of Hungary (now Bratislava, Slovakia) and his mother was of Martonvásár, Kingdom of Hungary. He studied (1886–1890) and worked (1894–1925) at the University of Vienna. After his PhD, in 1890, he studied at the University of Berlin, University of Göttingen and at the Sorbonne in Paris, but came back to Vienna in 1894. He discovered Zsigmondy's theorem in 1882.