Johannes Kepler, German astronomer and physicist, c 1600.
© Science Museum / Science & Society Picture Library
Johannes Kepler (1571-1630) became a follower of Copernicus whilst studying theology. He later worked with Tycho Brahe in Prague where he worked out the orbit of Mars. This led him to discover the laws of planetary motion. Kepler was also influential in the evolution of infinitesimal calculus.