Which preposition to use with caspian

to Occurrences 6%

The next day we came to another village nearer to the mountains, which, I understood, were called Caucasus, and that they reached from the eastern to the western sea, even passing the Caspian to the west.

on Occurrences 1%

This range of mountains extends between the Black Sea or Euxine on the west, and the Caspian on the east; this latter has no connection with the ocean, but is a vast lake called a sea, on account of its extent, being the largest lake in the world, and contains a great quantity of excellent fish.

unto Occurrences 1%

Then to the westward of the Caspian unto the Tanais or Don, and the Palus Maeotis, thence south to Mount Taurus[20], and north to the ocean, is all Scythia, and is divided among thirty-two nations.

Which preposition to use with  caspian