The history of the the wars between Rome and Parthia is complex, and unfortunately the sources are less than ideal in most cases. Sometimes the Parthians got the best of the fighting, while other times the Romans came out better. Capable Roman commanders like Ventidius Bassus proved that the tables of Carrhae could be turned on the Parthians when he used terrain favorable to the Romans to rout the Parthians. Later imperial invasions led by Trajan and Lucius Verus (actually Cassius Avidius for the latter) showed that a well led Roman army could march almost at will through Parthia.
I think one of history’s great what-ifs is what would have happened had Caesar lived to carry out his planned invasion of Parthia. For one thing, what was Caesar’s ultimate goal; to conquer Parthia (a tall order) or to decisively defeat them in war and dictate favorable terms (easy to imagine).
I think Caesar’s chances of success would have been high. The reasons for Crassus’ defeat were well known, so Caesar would not have made the same mistakes. Indeed it’s known that he planned to take a different invasion route through more favorable terrain. Caesar’s army would have included a larger cavalry force and more archers and slingers than Crassus’. Considering the success later Roman generals had against the Parthians (and Persians), it’s not hard to imagine Caesar emerging victorious in a war against Parthia.
I encountered the story of Crassus and Cassius reading an old history book by Rollins (translated from the French I think). I was so taken with this possible explanation of Cassius motivation, I am contemplating writing a play about it after I renovate my house. Can you recommend any good sources going into detail about this? So what do you consider were Crassus’ mistakes, aside from that catch-all Hubris? Speaking of Verus, didn’t he have a disaster in central Europe? As I said before, I think that Caesar’s motivation would have been to redeem the honor of Rome, besmirched by such a severe defeat.