Schilder, an expert on Dutch cartography, said Carolus merely copied both coastlines from earlier charts, while he believed that Plancius had copied some names from a chart by Mouris Willemsz, unknown to Wielder, that was published in 1608 or earlier by Cornelis Claeszoon (British Library, London). Willemsz's chart, which Schilder says shows Edgeøya labeled as "Groen Landt", doesn't show Edgeøya at all, but only shows a single coastline (not two) that is supposed to represent Spitsbergen. In fact, what appears to be Bjørnøya is shown to the southeast of Spitsbergen. Plancius had thus only created a duplicate Spitsbergen. Carolus, as well, made a duplicate Spitsbergen, as his "Morfyn" has an uncanny resemblance to Willemsz's "Groen Landt". This would indicate that the island would not have been discovered until 1616, as claimed by Edge. A 1617 letter written between the English whalers proves that Europeans had discovered the island at least at that late of date, or earlier, as Edge claims.