In a letter by Gerardus Mercator to John Dee, dated 1577, Mercator refers to a Jacob Cnoyen, who had learned that eight men returned to Norway from an expedition to the Arctic islands in 1364. One of the men, a priest, provided the King of Norway with a great deal of geographical information. In the early 19th century, Carl Christian Rafn mentioned a priest named Ivar Bardarsson who had previously been based in Greenland and turns up in Norwegian records from 1364 onward.