Mercenary life is recorded as a custom of Iron Age Spain, particularly in the central area of the Iberian peninsula. Departing from the native tribe and applying to serve in others was a way for economically disadvantaged youth to escape poverty and find an opportunity to use their fighting skills. Starting from 5th century BC, mercenary life would become a true social phenom in Hispania, with great numbers of fighters from distant lands coming to join the armies of Carthage, Rome, Sicily and even Greece, as well as other Hispanic peoples. They are repeatedly described by authors like Strabo and Thucydides as being among the best fighting forces in the Mediterranean Sea area, as well as, according to Livy, the most elite unit in Hannibal's army (id roboris in omni exercitu). Polybius cites them as the reason for the Carthaginian victory in several battles during the Second Punic War. Background Differentiating literal mercenaries from foreign vassals, brought to the battlefield through pacts or hostages instead of payment, is often difficult in ancient chronicles. Similarly, the exact provenience of Hispanic mercenaries is usually difficult to ascertain, as the terms used to refer to inhabitants of the Iberian peninsula are frequently vague, often using the generic "Iberian" to mean not only the coastal Iberian tribes, but any other people of Hispania. However, there is evidence that Hispania developed as a rich source of mercenary work during the early Iron Age. The reasons for this were mainly economic, as departing from the native tribe and serving in another, wealthier faction was a way for economically disadvantaged youth to escape poverty in their local lands, which were commonly subjected to sharp economic inequality. The main examples were found in Lusitania and Celtiberia, where cultivable terrains was concentrated among a few landowners, leaving mercenary life as the only alternative to banditry. However, the long history of tribal warfare and warrior culture between tribes in Hispania cannot be discarded as another factor in their choice. Natives from Balearic Islands and mountain folk from Cantabria were also recognized to have a strong mercenary tradition. Hispanic mercenaries would not work individually, but in small-sized units formed by friends and relatives, managed by their own chiefs and retaining their own cultural traits, including armament and tactics. Mercenaries having left Hispania didn't always return to their countries, and some of them, like Balearics, were known for spending all their gained