The Sertorian War was a civil war fought from 80 to 72 BC between a faction of Roman rebels (Sertorians) and the government in Rome (Sullans). The war was fought on the Iberian Peninsula (called Hispania by the Romans) and was one of the Roman civil wars of the first century BC. The Sertorians, a coalition of Celts, Aquitanians, Iberians and Roman and Italic rebels, fought against the representatives of the regime established by Sulla. The war takes its name from Quintus Sertorius, the leader of the opposition. It was notable for Sertorius' successful use of guerrilla warfare. The war ended after Sertorius was assassinated by Marcus Perperna, who was then promptly defeated by Pompey.
Origin of the war
During Sulla's civil war, Quintus Sertorius fought for the Marian-Cinna faction against Sulla. In 83 BC, Sertorius, after falling out with his faction's leadership, was sent to the Iberian Peninsula as its governor. Unfortunately for Sertorius his faction lost the war in Italy and Sulla dispatched an army which drove him from Iberia. After some wandering Sertorius ended up at Tingis in North Africa; where he helped the locals depose Ascalis, a pro-Sullan Tyrant. In Tingis he was met by an embassy of discontented Lusitanians, a fierce Celtic people, who implored him to lead them against the Sullan government which was extorting them back home. The Lusitanians chose Sertorius because of the mild policy he had pursued while governor in 82 BC. The Lusitani had a long history of resistance to Rome. Some historians have concluded that the Lusitani were seeking independence and by taking over the leadership of the movement Sertorius was opposing Rome itself.<ref>H. Berve, "Sertorius", Hermes 64 (1929) p. 221.</ref> Philip Spann considers this unlikely, as for Sertorius to accept such a treasonable offer would be to destroy any hope of returning to Rome. More likely the offer grew out of an acceptance by the Lusitani that they would not be able to defeat Rome and that their best hope was to assist the establishment in Rome of a regime sympathetic to them. Spann suggests that a major reason for Sertorius' acceptance was that it was becoming clearer that there would be no amnesty for him and his followers nor reconciliation with the regime set up by Sulla.
Sertorius returns to Iberia
In 80 BC Sertorius, after defeating off Mellaria a small naval force under Aurelius Cotta, landed in the Iberian Peninsula at Baelo, near the Pillars of Hercules (Gibraltar). Plutarch's account implies that Sertorius first went to Lusitania, organized the tribes and only then returned to the Baetis valley to defeat a Roman force under Lucius Fufidius (probably the governor of Hispania Ulterior). Spann suggests that a more probable sequence is that the battle of the Baetis River occurred during Sertorius' initial march to Lusitania.
Events of 80–77 BC
Sertorius‘ victory at the Baetis brought the majority of Hispania Ulterior back under his control. While he consolidated his power in the south-west (Ulterior) he sent his trusted lieutenant, Lucius Hirtuleius, to Hispania Citerior to take care of its governor, one Cotta, and the remaining Sullan forces on the Iberian Peninsula. Concerned at the growing threat, the authorities in Rome upgraded Hispania Ulterior from a propraetorian to a proconsular province, and appointed Quintus Caecilius Metellus Pius, Sulla's consular partner of 80 BC, as its governor. In 79 BC, with Metellus on his way, Marcus Domitius Calvinus (who had taken over Hispania Citerior from Cotta) crossed over into Hispania Ulterior, he found his passage blocked by the army of Hirtuleius who had fortified Consabura.
Hirtuleius used guerrilla warfare to wear down Domitius Calvinus's army while he lured him inland. Eventually a battle was fought at the Anas River; where Domitius was defeated; he either died in battle or was killed by his own troops who defected to the rebels.
Metellus, unaware of the disaster, had already sent one of his legates, Lucius Thorius Balbus, to provide assistance to Domitius, but he too was defeated, this time by Sertorius himself. Domitius Calvinus's replacement as governor was Quintus Calidius. Metellus entered Spain in late 80 or early 79 BC, basing himself at Metellinum (modern Medellin), made several thrusts into the interior, but was thwarted by Sertorius who used guerrilla tactics.