Ynglinga saga

In this, Snorri tells the story of how Odin and his people, the Asas, moved from their seat by river Tanakvisl (the river Don) at the Black Sea to escape Roman aggravations in the Caucasus, which is historically known to have occurred around 60 BC.

After establishing themselves first in Sachsen, they move to Fyn and Odense in Denmark, and finally to Svitjod where they settle at a place called Sithun (assumed to equal Sigtuna in Sweden).