Christiaan Huygens

Christiaan Huygens (1629–1695), son of diplomat Constantijn Huygens, was recruited by Louis XIV's minister Colbert in 1666 to become the founding leader of the French Royal Academy of Sciences in Paris. In 1656, he patented the first working pendulum clock, increasing timekeeping accuracy from 15 minutes a day to under 10 seconds.

Using lenses he polished himself, Huygens discovered Saturn's largest moon, Titan, in 1655, and solved the mystery of Saturn's strange appendages by proving it was surrounded by a thin, flat ring. In physics, his 1678 Treatise on Light formulated the wave theory of light and Huygens' Principle, explaining reflection and double refraction in calcite.