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 Museum
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 he nor the priest having actually seen the Inventio.
Cnoyen's account (originally in his own language; translations here based on Eva Taylor's version) mixes probable fact with what may have been his own attempts to research the background, stating that Greenland was first settled at the orders of King Arthur, whose army supposedly conquered the North Atlantic islands. He also refers to the "indrawing seas"- currents which drew ships northward, so that:
Of the visiting Franciscan, Cnoyen (or Mercator) summarised the priest's report thus:
In reality, the "book" may have been a detailed report, intended mainly to highlight the commercial possibilities offered by the North Atlantic following the decline of Norwegian interest in its colonies.
Nicholas was alive at the right time (very roughly- he is quite likely to have been a child in 1360), and had the right skills, but he was a Carmelite friar, not a Franciscan, and no earlier biographer indicates that he spent years travelling back and forth across the Atlantic on government business. There is another possible candidate, about whom, unfortunately, almost nothing is known. According to early 16th century literary historian John Bale, an Irishman named Hugh, who was a Franciscan, travelled widely in the 14th century, and wrote "a certain journey in one volume"- but again, whether or not this was the Inventio, no copy of it is known.
It is evident that the author of Inventio, if he actually travelled to the far north, did not actually reach the North Pole, which in no way resembles the description found in the book. However, it is likely that the author was speculating as to the source of the powerful magnetic force that underlies the functioning of the compass.
The concept of the pole as a magnetic mountain goes back at least to Roman times, but the author of Inventio Fortunata added other features to the picture as well as measurements. Whether or not the Inventio is the source of the medieval concept of the North Pole as a magnetic mountain surrounded by a circular continent divided by four powerful rivers, maps as early as Martin Behaim's 1492 globe depict the region in this way.
Johannes Ruysch's Universalior cogniti orbis tabula from 1508, features a marginal note mentioning the Inventio Fortunata:
Gerardus Mercator's world map of 1569 reflects his reading of Cnoyen's Itinerarium. It also features a marginal note alluding to the Franciscan's "discovery", but not to the book itself, which he never saw:
The 1569 map was the prototype for Mercator's influential and widely circulated Septentrionalium Terrarum of 1595, posthumously published by his son, and the maps in Ortelius's Theatrum Orbis Terrarum of 1570. Both show the same configuration of the arctic regions as the 1569 map.
In his letter to Dee, Mercator further quotes Cnoyen's description of the Northern regions:
The persistence of this idea of the geography of the far north persisted throughout the 16th and 17th century. This is probably due to the influence of Ruysch, Mercator, and Ortelius. Maps were only revised when the region was explored and mapmakers obtained knowledge of the true geography of the Arctic.
More interesting to modern researchers are the people the friar encountered- "pygmies" who may well be identical with the Skraelings referred to in old Norse texts about Greenland, predecessors of the modern Inuit.
In the letter, written in either December 1497 or January 1498, John Day says,