There were several Roman forces that were sent against the Rebels over the course of the Third Servile War.
A legions size varied greatly over time but were typically made up of around 5,400 soldiers, divided into ten cohorts each with 480 soldiers. Cohorts were divided into six centuries of eighty men each.
Army of GlaberEditThe army of Praetor Gaius Claudius Glaber was dispatched to quell the rebellion after several mercenary parties are defeated by Spartacus and the rebels and because he was responsible for Spartacus in Roman lands. Rome had not yet taken the rebellion seriously, and gave Glaber a small force to defeat the Rebels with. They engage Spartacus and the Rebels a number of times, clashing in the Mines and a nearby forest, the Arena of Capua, and briefly in the city of Atella.
Glaber is eventually replaced by the Senate with fellow Praetor and rival, Publius Varinius. Having just discovered where Spartacus is located he moves against the Senate's orders and marches on Vesuvius. When the army of Varinius is defeated, Glaber makes his prescence known and utilizes catapults on the Vesuvius Temple and forces the Rebels to flee to the top of Mount Vesuvius where he intends to starve them out. However, Spartacus uses a flanking maneuver against Glaber and the Rebels surround the Roman forces and ultimately defeat them, with Spartacus himself personally killing Glaber.
Army of VariniusEdit
Praetor Publius Varinius strikes against Spartacus through the use of Seppius, a Capua noble who has raised a contingement of mercenaries to take down the rebels. Following Seppius' death, the mercenaries are conscripted into the army of Gaius Claudius Glaber, Varinius' rival.
As the forces of Glaber prove to be unable to deal with Spartacus, Varinius is formally dispatched with his own army to defeat Spartacus. They march to Vesuvius where they meet a power rebel resistance. This leads to Varinius capture and the defeat of his forces until the arrival of Glaber. Varinius is killed as Glaber's forces march upon the Vesuvius Temple.
It is likely that any survivors from Varinius' army were automatically moved into Glaber's own forces.
Time Gap Between Vengeance and War of the DamnedEdit
Army of ScrofaEdit
Scrofa and his army are seen briefly in Enemies of Rome. At some point he was sent by the Senate to quell the rebellion. They fought Spartacus and his rebellion "on the banks of the Calor". This particular army was fought and defeated in the 6 month time gap between Vengeance and War of the Damned. As a Quaestor for the region of Lucania, Scrofa would have been in charge of a few local militias and mercenary cohorts to face the rebellion.
War of the DamnedEdit
Army of Cossinius and FuriusEdit
Cossinius and Furius proved to be the most difficult for the rebellion, but after several unsuccessful battles, the worst defeat being the Battle of Nuceria, Cossinius and Furius were located at a villa, where Spartacus, Crixus and Gannicus would infiltrate its defenses to kill Cossinius and Furius before they could join the bulk of their army, which was being harried by the main rebel force led by Agron.
Army of CrassusEditCrassus' army was composed of eight legions. Six of which were trained and equipped out of his own money. The other two were raised by the Senate and entrusted to his command after the failure of their previous commanders against Spartacus.
Army of ArriusEdit
The Praetor Arrius led a legion against the Army of Crixus in a bid to defend the city of Rome. Crixus utilized a few tactical maneuvers such as gigantic haysacks set on fire to break through the initial Roman defence before the two armies engaged. Arrius' army is completely destroyed and Crixus himself kills Arrius. This Rebel victory was short-lived, however, for the army of Marcus Licinius Crassus arrived and claimed the victory that Arrius could not.
Army of PompeEdit
Pompey commanded a private army of three legions, many of which were veterans whom previously served under his father. Throughout much of the 70's BCE, up until the final days of the Third Servile War in 71 BCE, Pompey and his forces were in Hispania, struggling to regain the province from its seccessionist Proconsul Quintus Sertorius, and his Lusitani allies in western Iberia.
Pompey had been sending scouts through the Republic and even one to Marcus Licinius Crassus. This particular scout group was ambushed and killed by Spartacus and his rebels.
While Spartacus and Crassus were clashing in the Battle of the Siler River, Pompey had moved with his army to intercept a large force of Rebels attempting to escape over the Alps. While Crassus had claimed victory over Spartacus and the main army, the victory of the war is ultimately given to Pompey.