Nikolaj Ivanovic Lobacevskij

Born: 1 December 1792
Dead: 24 February 1856
In: Kazan'


Short description:

He was a Russian mathematician and geometer, known primarily for his work on hyperbolic geometry, otherwise known as Lobachevskian geometry and also his fundamental study on Dirichlet integrals known as Lobachevsky integral formula.
William Kingdon Clifford called Lobachevsky the "Copernicus of Geometry" due to the revolutionary character of his work.


Wikipedia/other in-depth site