Bede

And I sent them to Iddo, etc. The Caspian Sea, as Orosius writes, rises from the northern region of the ocean, whose shores and deserted places around the ocean are uninhabited and uncultivated. From there, it extends southwards through long narrow passages, until, expanded over great distances, it is bordered by the roots of Mount Caucasus. It has many Hyrcanian and Scythian tribes from the east to the ocean, wandering widely due to the unfruitful spread of the lands. To the west, it has many tribes. …

Commentary on Ezra and Nehemiah ↗