of the first book of the 40 comprising Histories deals with the First Punic War. The accuracy of Polybius's account has been much debated over the past 150 years, but the modern consensus is to accept it largely at face value, and the details of the battle in modern sources are almost entirely based on interpretations of Polybius's account. The modern historian Andrew Curry considers Polybius "fairly reliable"; while Dexter Hoyos describes him as "a remarkably well-informed, industrious, and insightful historian". Other, later, ancient histories of the war exist, but in fragmentary or summary form. Modern historians usually take into account the later histories of Diodorus Siculus and Dio Cassius, although the classicist Adrian Goldsworthy states "Polybius' account is usually to be preferred when it differs with any of our other accounts". Other sources include inscriptions, coins and archaeological evidence. Armies Most male Roman citizens were eligible for military service, and would serve as infantry, with a better-off minority providing a cavalry component. Traditionally, when at war the Romans would raise two legions, each of 4,200 infantry and 300 cavalry. A small number of the infantry served as javelin-armed skirmishers. The others were equipped as heavy infantry, with body armour, a large shield, and short thrusting swords. They were divided into three ranks, of which the front rank also carried two javelins, while the second and third ranks had a thrusting spear instead. Both legionary sub-units and individual legionaries fought in relatively open order. It was the long-standing Roman procedure to elect two consuls each year to each lead an army. An army was usually formed by combining a Roman legion with a similarly sized and equipped legion provided by their Latin allies. Carthaginian citizens only served in their army if there was a direct threat to the city of Carthage. In most circumstances Carthage recruited foreigners to make up its army. Many were from North Africa which provided several types of fighters including: close-order infantry equipped with large shields, helmets, short swords and long thrusting spears; javelin-armed light infantry skirmishers; close-order shock cavalry carrying spears; and light cavalry skirmishers who threw javelins from a distance and avoided close combat. Both Iberia and Gaul provided small numbers of experienced infantry; unarmoured troops who would charge ferociously, but had a reputation for breaking off if a combat was protracted. The close-order African infantry would fight in a tightly packed formation known