Jan Jansson was a prominent 17th-century cartographer who published a history of maps by partnering with his brother-in-law, Henricus Hondius, on the Mercator-Hondius atlas. He expanded this into the multi-volume Atlas Major and Atlas Novus, which included sea atlases, town books, and historical atlases. His work was a major competitor to that of Joan Blaeu and significantly influenced mapmaking for nearly a century after his death.