At first glance, this nautical chart of the Baltic Sea appears to be a work of the publishing house Covens & Mortier, which operated in Amsterdam from 1685 to 1866. The network of lines is a means to facilitate navigation. An accurate depiction of the coastline is, thus, especially important. This is accompanied by several numbers indicating the depths of the seafloor. Upon closer inspection, however, the map is from the „Neptune François, ou Atlas nouveau des cartes marines“, a French volume of nautical charts created on the initiative of Jean-Baptiste Colbert (1619-1683) and published by Claude Gournai in Paris in 1693. It contains several nautical charts of the Baltic Sea, the North Sea and the European Atlantic coast. In the same year, Pieter Mortier (1661-1711), father of the two purported creators of the Baltic Map, Cornelis Mortier (1699-1783) and Johannes Covens (1697-1774), also published the “Neptune François” – without authorization by the King of France. His edition, however, was not used by navigators but served the purpose of a showpiece. No later than 1721, the publishing house ceased printing the volume. Existing copies of the whole volume as well as individual maps were sold off in the following years. Thus, the map of the Baltic Sea is not a “Nieuwe Caart” but rather an unauthorized variant edition.