Concerning the location of Thule, a discrepancy in data caused subsequent geographers some problems, and may be responsible for Ptolemy's distortion of Scotland. Strabo reported that Eratosthenes places Thule at a parallel 11500 stadia (1305 miles, or 16.4°) north of the mouth of the Borysthenes. The parallel running through that mouth also passes through Celtica and is Pytheas' base line. Using 3700 or 3800 stadia (approximately 420–430 miles or 5.3°–5.4°) north of Marseille for a base line obtains a latitude of 64.8° or 64.9° for Thule, well short of the Arctic Circle. It is in fact the latitude of Trondheim, where Pytheas may have reached land.