Johannes Kepler was born 1571 in Weil Der Statd (Which was in the Holy Roman Empire).  When he was six his mom took him to see a comet and that’s what made him interested in astronomy.  He was also a mathematician.  His first book established his reputation and his skills in astronomy.  Then he started working with Tycho Brahe, Tycho was also an astronomer.  They worked together for around a year before Tycho died, then Kepler became his successor.  Kepler is now known for his three laws of planetary motion.  First is that planets have eliptical orbits around their sun, second is that a planet’s speed increases when it nears the sun and decelerates when it is farther from the sun (According to, ” Kepler’s second law of planetary motion…a line between the sun and the planet sweeps equal areas in equal times”).   Third is “The square of an orbital period is proportinal to the semi-major axis of its orbit” or basically that if you know how long it takes the planet to orbit, then you can figure out it’s distance from it’s sun.   Kepler sent his books to important astronomers like Galileo.  He died in 1630 but his works are still remembered today.  He impacted history by inspiring Newton and creating a new way to do math which is calculus.