Johannes Kepler supported the heliocentric theory by Nicolas Copernicus
, defending it in his first major work, Mysterium Cosmographicum
(1596). In 1601 Kepler became the imperial mathematician to Rudolf II (emperor of the Holy Roman Empire), succeeding Tycho Brahe
. Using Brahe's data, between 1609 and 1619 Kepler developed his three laws of planetary motion in Astronomia Nova
and Harmonices Mundi
. Thanks in part to a telescope he received from Galileo
(they knew each other through correspondence only), Kepler also advanced the science of optics. His achievements in astronomy and mathematics shaped our current understanding of the solar system.