Inventio Fortunata (also Inventio Fortunate, Inventio Fortunat or Inventio Fortunatae), "Fortunate, or fortune-making, discovery", is a lost book, probably dating from the 14th century, containing a description of the North Pole as a magnetic island (the Rupes Nigra) surrounded by a giant whirlpool and four continents. No direct extracts from the document have been discovered, but its influence on the Western idea of the geography of the Arctic region persisted for several centuries. The story of the Inventio The book is said to be a travelogue written by a 14th-century Franciscan (Minorite) friar from Oxford who travelled the North Atlantic region in the early 1360s, making some half-a-dozen journeys conducting business on behalf of the King of England (Edward III). He described what he found on his first journey to the islands beyond 54 degrees north in a book, Inventio Fortunata, which he presented to the King. Unfortunately, by the time Atlantic explorers were seeking information in the 1490s, the Inventio had gone missing, and was only known through a summary in a second text, the Itinerarium, written by a Brabantian traveller from 's-Hertogenbosch named Jacobus Cnoyen (also known as James Cnoyen or Jakob van Knoyen; modern Knox). As will be discussed below, Cnoyen's summary was the basis for the depiction of the Arctic region on many maps, one of the earliest being Martin Behaim's 1492 globe. By the late 16th century, even Cnoyen's text was missing, so most of what we know of the contents of the Inventio Fortunata, other than its use on maps, is found in a letter from the Flemish cartographer Gerardus Mercator to the English astronomer John Dee dated April 20, 1577, now located in the British Library. Cnoyen's information came in a very round-about way. In 1364, a priest from one of the Atlantic islands had returned to Norway, bringing with him an astrolabe which he had received from the visiting Franciscan friar, in exchange for a religious book. He made a detailed report to the King of Norway. Copies still survive of a social and geographical description of Greenland by a local church official named Ivar Bardarson, who turns up in Norwegian records in 1364, so this much of Cnoyen's story tallies well with reality (although this report does not contain the sort of personal information relayed by Cnoyen). Cnoyen seems to have obtained his information from Norwegian sources some time later, neither