Claudius Claussön Swart, or Clavus Claudius, or Nicholas Niger, (September 14 1388-?), was a Danish geographer sometimes considered to be the first Nordic cartographer.

It is believed he was born in the village of Salling on Island of Fünen , Denmark. When he was 25 years old, that is in 1412-13, he started to travel around Europe and shows up ten year later (1423-24) in Rome. It is believed he travelled as far up as the 70°10' N. lat. In Rome he starts a friendship with the cardinal Giordano Orsini and the pope's secretary Francesco Poggio , who togheter with others are in working to update the old roman cartography. Claudius becomes the person contributing to a more realistic description of Nordic countries, in particular Iceland and Greenland.

Unfortunately, most of his work (including two maps) are lost but a copy has been preserved through the German cartographers Donnus Nicholas Germanus and Henricus Martellus Germanus . Until recently, more texts have been refound in the imperial library at Vienna.

Source: Catholic Encyclopedia