Actually, the name Thule first appear in Greek by Pytheas (whose original work is lost, but referenced to by several ancient writers). The origin of the name is unknown. Since Pytheas visited Germanic tribes, it is of course possible that it has a Germanic origin, but I'm not aware of any good evidence for that. Anyway, Pytheas sailed far north. How far is difficult to say. He described the midnight sun, the polar night and sea ice, but he could have reasoned his way to these descriptions of the Arctic. Or he actually went to Norway, Iceland or Greenland. Hard to tell. If not, Thule could have been the Orkney islands, Hebdrides, Shetland or the Faroe Islands. "Ultima" is Latin added later simply meaning "furthermost". It seems clear that he at least circumnavigated Britain, and Thule is supposed to be six days north of Britain. That could have taken him to Norway or possibly Iceland, but Thule is also supposed to be only one day from drift ice. That sounds unlikely in Norway (some inner fjords freeze in winter, but that doesn't quite fit Pytheas' description of something as far as it's possible to get. If he circumnavigated Iceland, ice can be reached within a day, but that sounds like a stretch. If he regarded the Faroe Islands as the northernmost part of Britain, Iceland should be reachable within six days, but my guess is that Thule is some island north of Britain (many candidates, the Faroes the furthest), or Norway (Møre perhaps), and the ice and the midnight sun are extrapolations.
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