Johann Janssonius (actually Jan Janszoon) was a Dutch cartographer and publisher who lived and worked in the 17th Century in Amsterdam.
Janssonius was born in 1588 in Arnhem to Jan Janszoon the Elder, a publisher and bookseller. Early in his life he learned the handcraft of printing and was employed by Jodocus Hondius (1563-1612), one of the most important publishers and cartographers of his time in the Netherlands. Shortly before the death of Hondius, Janssonius married Hondius’ daughter Elisabeth. In 1616, he manufactured his first maps which were images of France and Italy.
In 1618, Janssonius established his shop in Amsterdam „Op´t Water in de Paskaert” directly next to the shop of Willem Janszoon, who soon added Blaeu to his name. This Willem Blaeu, with his sons Joan and Cornelis, was for many years the fiercest competitor of Janssonius in the field of mapmaking. Jodocus Hondius had bought the copper printing plates of many maps by Mercator in 1604 and together with Johann’s father Jan, he published some editions of Mercator’s Atlas Minor. In 1638, Janssonius and Henricus Hondius, the son of Jodocus Hondius, published the Atlas Novus (later Novus Atlas), which still contained many maps by Mercator. At first, the work consisted of 318 maps in 3 volumes. In the following years, several editions were published which were extended with new maps, and which appeared in Latin, French, German and Dutch. In 1646, the atlas consisted of 6 volumes.
In 1658 the first edition of the Atlas Major, which, in addition to including maps published in the Novus Atlas, contained new works; it consisted of 9 volumes. In 1660 so many maps were added that it grew to include 11 volumes.
Blaeu’s Theatrum Orbis Terrarum , was the competitor to the Novus Atlas, and was published in 1634 with 204 maps in 2 volumes. If one compares the maps of Blaeu and Janssonius, there is often astounding similarity. As a result, Janssonius was often accused of having copied the maps of Blaeu. This may sometimes have been the case. Nevertheless, Janssonius also published maps of many regions that had not been previously published by Blaeu. It should also be noted that the first maps of Blaeu originate from printing plates which he bought from Jodocus Hondius Jr.
Other remarkable works of Janssonius include the town books, which were first published in 1652. These books consist of 8 volumes with 500 copper engravings of town views from across the world. In this publication, Janssonius outdid Blaeu, as his competitor only published views of the Netherlands and of Italy. The basis for the town views of Janssonius were the engravings from Civitatis Orbis Terrarum by Braun and Hogenberg. Janssonius bought these printing plates and just applied different figural decoration and new cartouches. Apart from the works of Braun and Hogenberg, he also copied some views by Merian and Blaeu.
In 1664, Janssonius passed away in Amsterdam. After his death, the printing house was run by his heirs under the leadership of his brother-in-law, Johannes van Waesbergen. The printing plates of the atlases and town books were sold in 1676. Some years later, they came into the ownership of Peter Schenk and Gerard Valck who were publishing further editions.