Kepler, a German astronomer, formulated three laws of planetary motion:

1. The Law of Ellipses: Planets move in elliptical orbits with the Sun at one focus.

2. The Law of Areas: A line joining a planet to the Sun sweeps out equal areas in equal times.

3. The Law of Periods: The square of a planet's orbital period is proportional to the cube of its average distance from the Sun.

These laws overturned the prevailing geocentric model of the universe, which had been proposed by Claudius Ptolemy. Kepler's laws were based on the meticulous observations of planetary positions made by Tycho Brahe, and they paved the way for Isaac Newton's later development of the law of universal gravitation.