Johannes Kepler was born on December 27, 1571 in Germany. Keplers father was a mercenary and Kepler was known to be a sickly child and spent most of his childhood reading books on astronomy.
In 1609, Kepler published his most popular Book Astronomia Nova. His book Stereometrica Doliorum formed the basis of integral calculus. Kepler's theories included that
planets move around the sun in an eliptical orbit, Kepler's third Law which states that the squares of the periods of planets are proportional to the cubes of the mean radii of their orbits,
Kepler's theories not only advanced the study of astronomy but helped lead to general acceptance for heliocentric astronomy.