In an effort to explain the magnetic anomaly that Marco Polo encountered near Hudson Bay, the Dutch cartographer Mercator postulated the existence of three magnetic poles in the Arctic. He also placed a message on his map (at the arrow) advising curious Europeans to read about Arctic isles in The Book of Marco Polo’s Travels.
Along the West Coast of North America, Mercator honored the explorations of Marco Polo. His map uses the place names that Marco Polo gave to regions of America’s West Coast in the 13th century. These include: Bergi, Anian, Quivira, and Toloman.