Maps of the period generally depicted a large continent named "Terra Australis Incognita" of highly variable shape and extent. This land was posited by Ptolemy as a counterbalance to the extensive continental areas in the northern hemisphere; due to a lack of exploration and various misunderstandings, its existence was not fully abandoned until circumnavigation of the area during the second voyage of James Cook in the 1770s showed that if it existed, it was much smaller than imagined previously. The first confirmed landing on Antarctica was only during the First Russian Antarctic Expedition in 1820, and the coastline of Queen Maud Land did not see significant exploration before Norwegian expeditions began in 1891. In 1513, Cape Horn had not yet been discovered, and indeed Ferdinand Magellan's voyage of circumnavigation was not to set sail for another six years. It is unclear whether the mapmaker saw South America itself as part of the unknown southern lands (as shown in the Miller Atlas), or whether (as Dutch thought) he drew what was then known of the coast with substantial distortion, but in any case, serious scholarship holds that there is no reason to believe that the map is the product of genuine knowledge of the Antarctic coast.