In the 70s BC, following the civil war between the aristocratic faction of Sulla and the remnants of the supporters of Marius and Cinna, the Roman popularist Quintus Sertorius refused to yield Spain to the Sullan dictatorship. His secession sparked the Sertorian War, during which Celtic polities in Mediterranean Gaul were subjected to troop levies and forced requisitions to support the military efforts of Metellus Pius, Pompeius Magnus ("Pompey the Great"), and other Roman commanders against the rebels. Some Celts, including perhaps the Helvii and Volcae Arecomici, supported Sertorius. After the renegade Roman was assassinated, Metellus and Pompeius were able to declare a victory, and the Helvii and Volcae were forced to cede a portion of their lands to the Greek city-state Massilia (present-day Marseilles), a loyal independent ally of Rome for centuries, located strategically at the mouth of the river Rhône and the staunch supporter of Pompeius.During Caesar's Gallic Wars, none of the Gallic "civitates" within the Narbonese province joined the pan-Gallic rebellion of 52 BC, nor engaged in any reported acts of hostility against Roman forces. The Helvian Valerii, in fact, play a key role in securing Caesar's rear militarily against Vercingetorix, who sent forces to invade Helvian territory. In his 1861 history of the Vivarais, Abbé Rouchier conjectured that Caesar, seeing the strategic utility of Helvian territory on the border of the Roman province along a main route into central Gaul, cultivated the Valerii by redressing the punitive measures taken against them by Pompeius. Caesar mentions the land forfeiture in his "Bellum Civile", while discreetly omitting any actions taken by his loyal Helvian friends against Rome in the 70s.