anti-Carthaginian army in the heart of its territory spread rapidly and many cities and towns rose in rebellion. Provisions, money and reinforcements poured in; eventually another 70,000 men according to the ancient Roman historian Polybius, although many would have been tied down in garrisoning their home towns against Carthaginian retribution. The pay dispute had become a full-scale revolt. The three years of war that followed are known as the Mercenary War and threatened Carthage's existence as a state. Opposing armies Carthaginian armies were nearly always composed of foreigners; citizens only served in the army if there was a direct threat to the city of Carthage. Roman sources refer to these foreign fighters derogatively as "mercenaries", but the modern historian Adrian Goldsworthy describes this as "a gross oversimplification". They served under a variety of arrangements; for example, some were the regular troops of allied cities or kingdoms seconded to Carthage as part of formal arrangements. The majority of these foreigners were from North Africa. Libyans provided close-order infantry equipped with large shields, helmets, short swords and long thrusting spears; as well as close-order shock cavalry carrying spears (also known as "heavy cavalry")both were noted for their discipline and staying power. Numidians provided light cavalry who threw javelins from a distance and avoided close combat, and javelin-armed light infantry skirmishers. Both Spain and Gaul provided experienced infantry; unarmoured troops who would charge ferociously, but had a reputation for breaking off if a combat was protracted. Specialist slingers were recruited from the Balearic Islands. The close-order Libyan infantry and the citizen militia would fight in a tightly packed formation known as a phalanx. Sicilians and Italians had also joined up during the war to fill the ranks. The Carthaginians frequently employed war elephants; North Africa had indigenous African forest elephants at the time. Both armies are likely to have been composed of similar types and proportions of troops, except the rebels were weaker in cavalry and lacked elephants. Prelude Mathos ordered two groups of rebels north to blockade the two main citiesother than Carthagethat had not already come over: the major ports of Utica and Hippo (modern Bizerte). Hanno, as the commander of Carthage's African army, took the field with an army of 8,000–10,000 men and 100 war elephants. Most of the Africans in his force remained loyal; they were accustomed to acting against their fellow Africans. His non-African contingent also remained loyal.