Dutch statesman and poet, mostly known for his work on scientific instruments (sometimes in conjunction with his younger brother Christiaan Huygens). He was also a chronicler of his times, revealing the importance of gossip, besides working as an amateur draughtsman of landscapes.
Constantijn was the eldest son of Sir Constantijn Huygens, a poet and statesman, and Suzanna van Baerle, the daughter of professor Barlaeus.
In 1649-1650 he accompanied Adriaen Pauw to England and toured through Belgium, France, Switzerland and Italy. In 1655 Constantijn moved to Paris. He joined the circle around Honoré Fabri. In the Hague he attended the salon organized by the wife of François Caron. In 1668 he married Susanna Rijckaert (1642-1712), a rich woman from Amsterdam.
Around 1650 when Christiaan Huygens became interested in microscopes and telescopes, Constantijn helped him with the construction of the lenses. In 1655 Christiaan discovered Titan, a moon orbiting Saturn. Between 1683 and 1687 Constantijn and his brother continued to make larger and longer focal length telescope objectives culminating in the very large tubeless aerial telescopes. He presented a 7.5 inch (190mm) diameter 123 ft (37.5 m) focal length aerial telescope objective to the Royal Society in 1690 that still bears his signature.
When William III of England became stadtholder in 1672, Constantijn Jr. had been appointed as his secretary. Constantijn participated in the campaigns against the French, in the Glorious Revolution, but did not attend the crowning. When William Blathwayt surpassed him as secretary, Constantijn was frustrated and in 1695 he received permission to return to the Dutch Republic.
From 1673 to 1696 Huygens kept a private diary, recording all aspects of early-modern court life in Holland and England. The book includes chapters on such subjects as the changing perception of time, book collecting, Huygens’s role as connoisseur of art, belief in magic and witchcraft, and gossip and sexuality at the court of William and Mary.
He was also skilled in drawing. In 1630 Constantijn Huygens Sr. had bought the castle of Zuilichem nearby Zaltbommel. Constantijn Huygens, Jr. made some drawings and paintings, depicting this castle in the period between 1650 till 1660. Constantijn was an art connoisseur and advised the setting up of the gallery in Kensington Palace.
He died on 2 November 1697.
Link to Wikipedia biography