Björnbo and Petersen have maintained in their monograph that Clavus must have been in Norway before he drew this map, and that amongst other things his remarkably correct latitude for Trondhjem must be due to his own observation of the length of the day at the summer solstice. Storm [1889, p. 140] seems also to have supposed that Clavus may really have been in Norway. To me it appears that his map and text are conclusive evidence against his ever having been there; for a man who had sailed to Trondhjem along the coast of Norway could not possibly have produced a cartographical representation of the country so entirely at variance with reality as Clavus has done, however ignorant we may suppose him. The fact in itself that "Trunthheim" (Trondhjem) or "Nedrosia" is placed at the extremity of the south side of the south-western promontory of the country is extraordinary. If he had come there asleep he could not have got any such idea; and for a man who had sailed in through the long channel of the Trondhjem fjord up to the town it is incredible. It is equally incredible that a man who had sailed along the coast from Stavanger and Bergen to Trondhjem could place the latter town in a latitude 10' to the south of Bergen, and only 10' to the north of Stavanger. We are not justified in attributing to Clavus such an entire lack of power of observation, especially if we are to suppose him capable of determining with remarkable accuracy the length of the longest day at Trondhjem. That Trondhjem is placed to the west of Bergen and Stavanger, that the Dovrefjeld is called a high promontory, while on the Nancy map it was inland, that Hamar ("Amerensis") is put on the sea-coast, etc., all shows the same want of knowledge of the country and its configuration. The names he may have taken from an itinerary or other sources, and, as already suggested, it is not unlikely that he may have found in the papal archives a fairly correct statement of the latitude (or length of the longest day) of Trondhjem, which was an archbishop's see. That the towns he gives are just those that are the heads of dioceses is perhaps an indication of a connection with the Vatican.
"Norway has eighteen islands, which in winter are always connected with the mainland, and are seldom separated from it, unless the summer is very warm," and that "'Tyle' [Thule] is a part of Norway and is not reckoned as an island, although it is separated from the land by a channel or strait, for the ice connects it with the land for eight or nine months, and therefore it is reckoned as mainland. The same applies to the sea 'Nordhinbodnen' [Nordbotn], which separates 'Wildlappenland' from 'Vermenlandh'[261] and 'Findland' by a long strait, since the countries are united by almost eternal ice."