This was a shared interest with the Huygens family who lived close by (Christiaan Huygens Sr was councillor of state). The younger De Gheyn studied in Leiden with Constantijn and Maurits Huygens, who remained lifelong friends.
The younger De Gheyn had a common interest with the Huygens family, who lived close by. Christiaan Huygens Sr was a state councillor, while the younger De Gheyn studied in Leiden alongside Constantijn and Maurits Huygens, who were lifelong friends.