What did Christiaan Huygens invent in 1657?

Christiaan Huygens, a Dutch scientist from the 17th century, was a pioneer in developing the field of horology. He was an established mathematician in his day. Christiaan was also a scholar in physics and astronomy. He had correspondence with several eminent scientists and mathematicians of his time, such as Descartes and Pascal.

Christiaan invented the pendulum clock in the year 1657, when he was a 28-year old young man. His innovation effectively reduced the loss of time, from about 15 minutes to an astonishing 15 seconds for a single day. He patented the technology in 1657.