Whose equations described the motion of planets before modern computers?

Johannes Kepler, working from Tycho Brahe’s observations, published his three laws of planetary motion between 1609 and 1619. These laws showed that planets move in elliptical orbits, sweep out equal areas in equal times, and obey a relationship between orbital period and distance from the Sun. Kepler’s rules were a breakthrough because they replaced older circular models with a much more accurate system. They later became a foundation for Isaac Newton’s theory of gravitation.