What conditions would be needed for Spartacus to defeat Rome?

Question

In a certain project of mine, people encounter humans (cyborgs, really) from an parallel Earth in which the slave rebellion led by Spartacus successfully invaded Rome, overthrowing the Romans and making them their slaves (this assumes Spartacus was not the ahead-of-his-times-abolitionist Hollywood likes to imagine he was).

I've been told part of the reason his rebels lasted as long as they did was because much of the Roman army was fighting in what is now called Spain- what would be needed for the rebels to topple the Empire's capitol before the legions could return and (another question, I know) what would those rebels need to do to keep the legions from retaking the city?

Answer 1

It's one thing for Spartacus' army of escaped slaves, led by a relatively few gladiators, to have been able to fight off the Roman legions, and escape far away to form their own nation. (In fact, they could have done that, but too many of his followers wanted to stay in Italy, and so the army hung around in northern Italy long enough that it was finally defeated, at least partly by attrition.)

It's quite another to actually occupy and rule Rome itself. It's simply not a realistic scenario to stipulate that an army of escaped slaves, lead by a relatively few fighters trained for arena combat -- not trained in the strategy of fighting a war -- would be able to rule Rome. If they did, it wouldn't be for long. Rome's population is much too large, and the idea of being ruled by former slaves would set just about every man's hand against the rulers. The idea of a slave revolt terrified the Romans -- for good reason. It's simply not believable that they would cooperate with being ruled by escaped slaves.

Perhaps a plausible case could be made out for the rebel army to burn Rome to the ground. Even then, the rest of the country and any surviving legions would be roused against them. Legions in outlying provinces would march back home to retake Italy from the usurpers, once word got to them. All the legions, not just a few. They'd certainly let the outlying provinces go, if necessary, in order to retake and protect Rome itself.

Remember the lesson of Iraq: It's relatively easy to topple a government. It takes many, many more troops to occupy a country -- or even a large city -- and keep order, when the inhabitants refuse to cooperate.

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If you want to salvage this scenario, I suggest having Spartacus' army escape to Gaul. Unfortunately, Vercingetorix lived in a later era; there's no overlap with the lifetime of Spartacus. But you could stipulate that Spartacus' revolt inspired some Gallic chieftain to unite the Gauls against Rome, as Vercingetorix did in our timeline. Add a few alliances with other nations chafing under Rome's rule, and the barbarian invasion could have caused the fall of the Roman Empire centuries before it happened in our timeline.

You still don't wind up with Spartacus ruling Rome, though. Perhaps some Gallic or Germanic chief would, altho historically the barbarians who successfully invaded Rome (at least the first few times) sacked it and left; they didn't stick around to settle down and rule Italy. But if they had, that would at least be much more plausible than Spartacus becoming ruler of Rome.

Answer 2

Basically Spartacus would have to gain the kind of fame and popular support that Caesar did, and then march in and declare himself the boss.

That's not going to be easy for him to do. Caesar had the support of Rome during his fame-building stage whereas Spartacus has Rome trying to kill him. The only two viable options would be either to leave Italy and build fame elsewhere until everyone likes and respects him enough that he can either take over Rome or raise a rebellion against Rome amongst the outlying territories, or to sneak into the city and assassinate the senate. In the former case he then has to win a war against a major military power (possible, but difficult.) In the latter case he has however many months it takes the legions to march back to Rome to show everyone that he's no worse than, and possibly less corrupt than, the former senate. Everyone in the Legions suddenly getting a pay/ration increase due to bureaucrats no longer skimming the money as it goes past would probably convince them to side with him...

As an alternative, consider having Carthage win the war 70 years previously. That was actually a pretty darn close fight with just a couple of strategic mistakes on the Carthaginian side (likely due to poor communication) causing them to lose. The world would definitely have turned out differently if the "Trade with you and build a vast commercial network" empire had won instead of the "Enslave you and steal all your stuff" empire. In the last several decades archaeologists have been discovering that much of what was known about Carthage was simply Roman propaganda, and that many of the great technological innovations credited to Rome were Carthaginian in origin. Carthage was wealthier, more technologically advanced, and an even larger economic powerhouse than Rome. They just made the mistake of not taking Roman threats seriously and giving the Romans a chance to build up their power instead of grinding the Romans into dust when they first started talking about destroying Carthage.

Answer 3

As noted, Spartacus actually won several battles, but could never defeat Rome. The Romans were particularly bloody minded people who simply refused to concede defeat. You could destroy legions but the Romans would simply raise some more and keep coming after you (as Hannibal could attest). Essentially the Romans would not be defeated unless they said so, and in the Third Servile War this is quite clear, the Romans sent local militias, raised legions and when they were defeated appointed new commenders and raised even more legions until the job was done. (the return of Pompey's legions from Hispania actually made little difference to the final outcome, and more legions were fighting the Third Mithridatic War and could have become available to crush the rebellion later).

Under these conditions, Spartacus is on the losing end of a war of attrition. the Roman military machine can turn out a constant supply of trained and armed men, and also has the industrial and logistical means to arm, equip, feed and transport the legions against Spartacus and his army. Spartacus, on the other hand, needs to try to live off the land and keep what is essentially an untrained mob together. The demands of day to day survival would overwhelm their cohesion in the long term, and losses form battles, disease, desertion etc. would not be made up in any effective manner.

The Greek "Ten Thousand" were a cohesive force through their march up country hundreds of years earlier because they were free men with a common culture and goal. Tens of thousands slaves from all across the territory of the Res Publica Roma would not be sharing much in common outside of a hatred of their slave owners and a desire to escape slavery.

The only reason the revolt lasted as long as it did and was as successful as it was had more to do with the majority of the Legions engaged in foreign campaigns. As well, Roman society had been severely rocked by the Social Wars only a decade earlier, so the Romans were not as cohesive as they might have been, allowing the slaves more time to gather and organize than might have otherwise been the case.

So Sparticus could only have "won" by fleeing italy entirely. Where he could have gone is questionable, since the Romans were already spread across much of the known world, and even a hostile empire looking to unbalance Rome would have had a hard time reaching them

Extent of the Res Publica Roma near the time of Spartacus

So the short answer is the Slave army has no realistic chance to conquer or rule Rome, and would have difficulty finding an easy escape from any territories occupied by the Romans.