The son of a bookseller and publisher who had worked with Jodocus Hondius Sr., Jan Jansson Jr. (1588 -1664), married Jodocus’ daughter Elisabeth in 1612. In direct competition with the Blaeu’s, he and his brother-in-law Henry re-issued the Mercator-Hondius Atlas beginning in 1633. They redrew or replaced many of the maps in the original atlas. After the death of Henry, Jansson continued the business and expanded the Atlas into the Atlas Novus. This work was highly regarded but overshadowed by the Blaeu family works.
Jansson also issued a revised reprint of Braun and Hogenberg’s Civitates Orbis Terrarum, retaining many of the existing plates, but also adding a number of new ones. Other atlases that he published include Andreas Cellarius’ celestial atlas and George Hornius’ classical atlas.