Ancient map of Arctic's seas, northern Europe, 1595

"Septentrionalium Terrarum descriptio" is one of Mercator's most famous maps and was first published in 1595 as part of his atlas "Atlas sive Cosmographicae Meditationes de Fabrica mundi et fabricati figura," which you mentioned earlier. This map was significant because it provided a groundbreaking representation of the Arctic and northern regions.

Mercator's "Septentrionalium Terrarum descriptio" was based on various sources, including his own observations and information gathered from explorers and navigators of the time. The map depicted the lands and seas of the Arctic, northern Europe, and parts of North America. It was highly influential and helped shape the understanding and exploration of these regions.

One notable feature of the map is the inclusion of a large island called "Frislanda," which is now known to be a fictitious place. The map also featured various other geographical features, including rivers, mountains, and coastal details.

"Atlas sive Cosmographicae Meditationes de Fabrica mundi et fabricati figura," is actually a collaboration between Gerardus Mercator and Jodocus Hondius. Gerardus Mercator (1512-1594) was a Flemish cartographer, geographer, and mathematician who is best known for his work in cartography, particularly for his creation of the Mercator projection, a cylindrical map projection that greatly facilitated navigation.

Jodocus Hondius (1563-1612) was a Dutch engraver and cartographer. He was a skilled mapmaker and collaborated with Mercator on several projects. After Mercator's death in 1594, Hondius acquired his copper plates and continued to publish editions of Mercator's atlas, which eventually became known as the Mercator-Hondius atlas.

The work "Atlas sive Cosmographicae Meditationes de Fabrica mundi et fabricati figura" is a Latin phrase that translates to "Atlas or Cosmographic Meditations on the Structure of the World and the Structure of the Created Figure." It was first published in 1595 by Jodocus Hondius, a year after Mercator's death. The atlas consisted of a collection of maps, including world maps, regional maps, and maps of individual countries.

The collaboration between Mercator and Hondius was significant because it combined Mercator's expertise in cartography with Hondius' skills in engraving and publishing. Their collaboration resulted in the production of high-quality atlases that were widely used and influential during the 16th and 17th centuries.