Johannes Janssonius (1588–1664), also known as Jan Jansson or Jan Janszoon, was a prominent Dutch cartographer, publisher, and engraver active in Amsterdam during the 17th century. Born in Arnhem into a family of publishers and booksellers, he married Elisabeth de Hondt, daughter of the famous cartographer Jodocus Hondius, which strengthened his position in the cartographic world. Janssonius started publishing maps in 1616, focusing on regions such as France and Italy.
He expanded his business aggressively, owning bookstores across Europe in cities like Frankfurt, Stockholm, Copenhagen, and Berlin. Johannes Janssonius is best known for his work in continuing and expanding the Hondius atlases, later renamed Atlas Novus and eventually evolving into the Atlas Major, a comprehensive multi-volume atlas with detailed city maps, maritime charts, and celestial maps. His publications were popular in several languages and highly influential in European cartography.
