The correct relations in the length of degrees of latitude and longitude are maintained in the first case along the latitude of Thule and the equator, in the second along the parallel of Agisymba, the equator and the parallels of Meroe, Syene and Thule.
In 795 (February 1-August 1) Irish hermits had visited Iceland; on their return they reported the marvel of the perpetual day at midsummer in "Thule," where there was then "no darkness to hinder one from doing what one would."
Here occurs the earliest mention of Vinland, and here are also references of great interest to Russia and Kiev, to the heathen Prussians, the Wends and other Slav races of the South Baltic coast, and to Finland, Thule or Iceland, Greenland and the Polar seas which Harald Hardrada and the nobles of Frisia had attempted to explore in Adam's own day (before 1066).
To this he added the account of Thule (which he placed six days' voyage north of Britain) and the adjoining regions, in which there was no longer any distinction between air, earth and sea, but a kind of mixture of all three, resembling the gelatinous mollusc known as pulmo marinus, which rendered all navigation and progress in any other mode alike impossible.
At the same time he heard vaguely of the existence of a large island to the north of it - probably derived from the fact of the Orkneys and Shetlands being really found in that position - to which he gave the name of Thule.