Christian Huygens (1629-1695), a Dutch scientist and inventor of the pendulum clock. Huygens had a keen interest in astronomy; using a telescope he had made, he first identified Saturn's rings and Saturn's largest moon, Titan. His work in astronomy required accurate timekeeping, and in 1656 he patented the first pendulum clock, which increased the accuracy of time measurement from 10 minutes to 10-second precision. Huygens also built several pendulum clocks to determine longitude at sea, and derived the law of centrifugal force for uniform circular motion.
Huygens Biography (University of St. Andrews, Scotland, School of Mathematics and Statistics)