Hermann Minkowski (1864-1909), German mathematician. Minkowski was appointed professor at the universities of Konigsberg (1895), Zurich (1896) and Gottingen (1902). He taught Albert Einstein at Zurich. Minkowski's most important work was a mathematical description of spacetime, originally published in 1907. Spacetime uses four dimensions, the three space dimensions and a time dimension. Minkowski's spacetime was used by Einstein in his theory of special relativity. Minkowski also discovered a new branch of number theory, the geometry of numbers. Photographed circa 1890.