The epic battle to liberate Spain from Roman rule is a masterclass of ancient guerilla warfare, recounted by the author of Ancient Rome on 5 Denarii a Day.

In the year 82 BC, after a brutal civil war, the dictator Sulla took power in Rome. But among those who refused to accept his rule was the young army officer Quintus Sertorius. Sertorius fled, first to Africa and then to Spain, where he made common cause with the native people who had been savagely oppressed by a succession of corrupt Roman governors. Discovering a genius for guerilla warfare-and claiming to receive divine guidance from Artemis-Sertorius came close to driving the Romans out of Spain altogether.

Rome responded by sending reinforcements under the control of Gen. Gnaeus Pompeius Magnus, who would go on to become Pompey the Great. The epic struggle between these two commanders, known as the Sertorian War, is a masterclass of ancient strategy and tactical maneuver. Massively outnumbered, Sertorius remained undefeated on the battlefield, but was eventually assassinated by jealous subordinates, none of whom proved a match for Pompey.

The tale of Sertorius is both the story of a people struggling to liberate themselves from oppressive rule, and the story of a man who started as an idealist and ended almost as savage and despotic as his enemies. But above all, it is the story of a duel between two great generals, fought between two different styles of army in the valleys of the Spanish interior.