IMO kind of a silly idea. The Marines, while their ammo and fuel lasted, would be able to destroy any group that tried to resist them. But they’re still only a couple thousand men. If they try to spread out and occupy territory, they’d be defeated in detail. So they’d have to stay together and could control any 5 or 10 square miles they choose, but only that one patch.
They’d be like the British in our Revolution. March anywhere they choose, with rare exceptions such as Saratoga, but their control exists only within their own lines. Or the Americans in Vietnam. Combat power does NOT necessarily translate directly to political power.
What would actually happen, IMO, is that various ambitious Roman politicos would see an opportunity to grab power and would approach the Marines to strike an alliance. This would be the Marine’s only chance for long-term survival, so they’d shortly be co-opted into the Roman political system.
Cortez and Pizarro won because they were able to take out the leadership, and because they had the boats to get to where they needed to be.
The question for the Marines, has to be where? Rome was big, much bigger than the Incan or the Aztec empires. They also had naval supremacy. The Marines, as good as they are, how are they going to get across the Mediterreanean? You can’t exactly fit an Abrams on a boat and sail it across the med, not with the technology back then.
Two things, one.
The Romans were good, really good, at political cohesion and negotiation. For the longest time they didn’t fight wars, except against Carthage. Since you’re dropping them in against Augustus, good luck with that. The military deployment in 23 BC, would be after the defeat of Antony and his consolidation of power.
If you are going to win, the Marines would have to figure out a way to kill Caesar Augustus, and take over a legion for themselves. Then, they could probably do some serious damage, but it would take years to consolidate control.
Two, co opting works both ways. If Octavian gets wind of a unit of men with technology far beyond his own, I wouldn’t be surprised if Octavian’s response was to march to meet them personally.
With women. Meet the marines in parley and make it clear to them that they are stranded without any options. Give them options, give them a way out, give them a villa, or command positions if they would swear loyalty to the Emperor.
How many of the typical marines in the typical unit are going to say yes?
My question. Why would the Marines want to take over the Empire or even fight them? They might come to terms with Agustus—trade a few things for food and wait to reverse anything and return home. They might join the Roman to seize China and crush Germany? It wouldn’t take much—just show them how to make gun powder and crude cannons. An interesting idea.
I thought of one alternative history idea. What if Mexico won the battle of BuenaVista and the Mexican War? California stays with Mexico—they find the gold and become a great power. or
What if a time traveler went back to Germany in 1943 and gave Hitler the history of the war, and ways to improve his V-1s & V-2, Jets and tanks maybe even the A-Bomb! In exchange he ends the Holocaust? Would he do it?