Johannes Kepler was born in a small town of Weil der Stadt in Swabia, and moved to nearby Leonberg with his parents in 1576. His mother was the daughter of an innkeeper, and his father was a mercenary soldier. His father is believed to have died in the war in the Netherlands, when Kepler was only 5. Kepler's early education began in a local school and then at a nearby seminary. After that, he enrolled at the University of Tubingen. There, he met mathematics professor, Michael Maestlin, who became his mentor. Maestlin was one of the earliest astronomers to subscribe to Copernicus's heliocentric theory, although in his university lectures he taught only the Ptolemaic system. Only in what we might call graduate seminars did he acquaint his students, among whom was Kepler, with the technical details of the Copernican system. Maestlin was a proponent of the heliocentric model of the solar system and planets introduced by astronomer Nicolaus Copernicus.
Johannes Kepler, too, accepted this theory immediately, seeing the hand of God in its simplicity and becoming interested in astronomy.
Giving up his plan of becoming a clergyman, Johannes Kepler departed the University of Tubingen in 1594 to accept a chair in mathematics and astronomy at the university in Graz, Austria. After taking this position, he developed a complex hypothesis to explain the distance between the orbits of planets. It was said that from this teacher Kepler focused his knowledge and studies to the heliocentric form of astronomy. Kepler is most chiefly remembered for discovering the three laws of planetary motion. If not for Kepler assisting Tycho Brahe, Kepler would never have found the 3 laws of planetary motion. When assisting Tycho Brahe, Brahe feared that Kepler would surpass him and become the premiere astronomer of their day.