A diagram for Christiaan Huygens's explanation of light as wave phenomena. Huygens (1629-1695) was a prominent Dutch mathematician, astronomer, physicist, probabilist, horologist and scientist. Huygens is remembered especially for his wave theory of light. He investigated the use of lenses in projectors and is credited as the inventor of the magic lantern. His work included early telescopic studies of the rings of Saturn and the discovery of its moon Titan. His invention of the pendulum clock was a breakthrough in timekeeping. He also developed a balance spring watch in the same period as Robert Hooke.