Caracalla was a bad guy. Things went to his head after the kidnapping the king thing, and being that tyrants can't ever get enough, well Caracalla set his sights on Parthia. Caracalla didn't need a foreign king's advice because he believed he was being guided by a ghost: Alexander the Great. Bibi can't compete with that. Great caesar ghost. Capturing Osroenean king Abgar was such a slam dunk, how could conquering a whole country be any harder? Boom like that and it is all done and over. Easy if you don't think about it. And this is where it gets interesting.
QuoteInvading Parthia Caracalla ravaged a large section of the country around Media by making a sudden incursion, sacked many fortresses, won over Arbela, dug open the royal tombs of the Parthians, and scattered the bones about. This was easy for Caracalla to accomplish as the Parthians did not even join battle with him. The barbarians took refuge in mountains beyond the Tigris to complete preparations, Caracalla suppressed this fact in a letter to the Senate and took to himself as much credit as if he had utterly vanquished the foe, whom as a matter of fact he had not even seen.
Caracalla was assassinated on 8 April 217 while urinating at a roadside. His troops hated his brutality. People who are stuck on themselves can really piss other people off. Some things never change. The Parthians regrouped fighting the Romans to a standstill at the Battle of Nisibis. The new emperor Macrinus, brought the war to an end in 218 by paying the Parthians reparations of possibly as much as 50 million denarii.
In today's money that is $2.59 Billion USD.
If Trump could buy his way out with that right now, it would be money well spent. As things are, Trump the 'deal maker,' can't make a deal.
Caracalla's "easy" war was one of the worst ROI (Return on Investment) events in imperial history. Rome became unstable.
Rome often "won" the battles in Mesopotamia but lost the peace because the cost of occupying "Persia" was higher than the value of the land itself. The U.S. has a $1.5 trillion military budget and the closure of the Strait of Hormuz is costing billions more. The Roman lessons about this is that winning the war is often the easy part. Surviving the carnage of the economic aftermath can destroy an empire.
As of March 2026, the U.S. National Debt has climbed past $38.8 trillion. The cost of the first 100 hours of the Iran conflict is estimated to be $3.7 billion. None of which was in the budget. Trump breaks the bank. Just like he was running a casino into the ground.