Caesar wanted to do a lap around the Black Sea after defeating the Parthians and work his way home through what was then Sythia. Depending on how far they got,

Caesar wanted to do a lap around the Black Sea after defeating the Parthians and work his way home through what was then Sythia. Depending on how far they got, and there's more than a good chance that the Parthians may have destroyed any army sent against them. If not, then the Romans would have had to face the steppe horse archers a few hundred years earlier than otherwise. And that would never be easy.