In 1601 Johannes Kepler became the imperial mathematician to Rudolf II (emperor of the Holy Roman Empire), succeeding Tycho Brahe. Kepler supported the heliocentric theory by Nicolas Copernicus, defending it in his first major work, Mysterium Cosmographicum (1596).
Johannes Kepler was born in Weil der Stadt in southwest Germany. His paternal grandfather, Sebald Kepler, was a respected craftsman who served as mayor of the city; his grandfather was an innkeeper and mayor of the nearby village.
Johannes Kepler was a German mathematician, astronomer and astrologer, and key figure in the 17th century scientific revolution. He is best known for his eponymous laws of planetary motion and his works Astronomia nova, Harmonices Mundi, and the Somnium..