The Mercenary War (c.240 BC) — also called the Libyan War and the Truceless War by Polybius — was an uprising of mercenary armies formerly employed by Carthage, backed by Libyan settlements revolting against Carthaginian control.
The war began as a dispute over the payment of money owed the mercenaries between the mercenary armies who fought the First Punic War on Carthage's behalf, and a destitute Carthage, which had lost most of its wealth due to the indemnities imposed by Rome as part of the peace treaty. The dispute grew until the mercenaries seized Tunis by force of arms, and directly threatened Carthage, which then capitulated to the mercenaries demands. The conflict would have ended there, had not two of the mercenary commanders, Spendius and Mathos, persuaded the Libyan conscripts in the army to accept their leadership, and then convinced them that Carthage would exact vengeance for their part in the revolt once the foreign mercenaries were paid and sent home. They also persuaded the combined mercenary armies to revolt against Carthage, and various Libyan towns and cities to back the revolt. What had been a hotly contested "labour dispute" exploded into a full-scale revolt.
Heavily outmatched in terms of troops and supplies, an unprepared Carthage fared poorly in the initial engagements of the war, especially under the generalship of Hanno the Great. However, as the war progressed, Hamilcar Barca was first given joint command with Hanno, and finally full command of Carthage's army. Even though he was vastly outnumbered and faced a hardened mercenary army which he himself had led against the Roman Legions, Hamilcar displayed superior military leadership and clever use of psychology in the conflict. His talents eventually won over a portion of the mercenary armies to Carthage's side, and at the decisive Battle of "The Saw", Hamilcar destroyed the majority of the rebel army. With the aid of a Carthaginian general Hannibal (not the famous Hannibal Barca who was Hamilcar's son, but another general of that name), and reinforcements under the command of Hanno the Great, the remnants of the mercenaries were finally put down.
The war had repercussions for Carthage, both internally, and internationally. Internally, the victory of Hamilcar Barca greatly enhanced the prestige and power of the Barcid family, whose most famous member, Hannibal, would lead Carthage in the Second Punic War. Internationally, Rome used the "invitation" of the mercenaries that had captured Sardinia to occupy the island, and when Carthage prepared a force to pursue the remnants of the mercenaries there, Rome claimed that Carthage's military preparations were to be used against Rome, and declared war on Carthage. Carthage immediately surrendered rather than enter into a conflict with Rome again, giving up all claims on Sardinia, and placing themselves in debt to Rome by another 1,200 talents.
In 241 BC the First Punic War between Rome and Carthage came to an end with Carthaginian defeat. As part of the terms of the treaty, Rome demanded that Carthage give up "all islands lying between Sicily and Italy", immediately pay Rome a sum of 1,000 talents of gold, and pay a further 2,000 talents over a period of 10 years . After meeting the Roman demands, a destitute Carthage now found itself in a quandary: it had employed numerous mercenaries in the First Punic War and now found it difficult to pay them .
This was a problem, as some 20,000 mercenaries, formerly under the command of Hamilcar Barca (who had resigned his command at the end of the First Punic War), would shortly be returning from Lilybaeum (modern Marsala in Sicily) to Carthage. Concerned about the possibility of a large, disgruntled, mercenary force encamped near Carthage, Gesco, the Carthaginian commandant responsible for transporting the mercenaries from Sicily, attempted to deploy the mercenaries throughout Carthaginian territory. It was his plan to bring the mercenary units back to the capital one at a time, for demobilization and payment. However, delays by the Carthaginian government, and a belief that the mercenaries could be convinced to settle for less than their agreed wages, resulted in the eventual gathering of most of the mercenary armies near Carthage. Wary of such a large foreign army near the capital, and alarmed by the disruptive effects they were having on the city, the Carthaginian government convinced the mercenaries to withdraw to the nearby city of Sicca Veneria (Modern El Kef), 170 km south-west of Carthage, taking their families and baggage trains with them.
Once in Sicca Veneria, the mercenaries collaborated on a list of demands and "submitted that this was the sum they should demand from the Carthaginians". When Hanno the Great met with officers from the mercenary companies, he rejected their demands, claiming that Carthage could not possibly pay such an exorbitant sum due to her post-war indemnities to Rome.
The mercenaries were happy at the rejection of their demands, and were mistrustful of Hanno, much preferring to deal with the commanders they had served under in Sicily, such as Hamilcar, who had seen their worth and furthermore made promises to them. Unsurprisingly, due to the mistrust and difficulties in communication (the mercenaries were from many different nations, speaking many different languages), the negotiations quickly broke down. A force of mercenaries, about 20,000 strong, armed themselves and marched towards Carthage, seizing the town of Tunis some 21 km from Carthage.
Realizing their error in letting such a large foreign army gather in the first place, and also realizing that they had released the family and belongings of the mercenaries as well and thus had given up a bargaining position, the Carthaginian government had no choice but to capitulate to the mercenary demands.
Not willing to deal with Hanno again, and feeling insulted by Hamilcar for not having met with them in the first round of negotiations, the mercenaries agreed to negotiate with Gesco. Given their newly strengthened bargaining position, the mercenaries vastly inflated their original demands, even requiring the extension of the payments to the Libyans whom Carthage had conscripted (and who were not mercenaries) as well as other Numidians and to the escaped slaves and the like who had joined their ranks against Carthage. Once again Carthage had no choice but to agree..
Despite the more generous settlement, two mercenaries, Spendius and Mathos, organized a rebellion, based on speculation that after the foreigners left Africa, Carthage would be unwilling, or simply unable, to pay those remaining. In 240 BC Gesco and other officials were taken prisoner by the mercenary leadership and open warfare ensued.
The Libyan population, discontent with Carthaginian rule, supported the rebels. Carthage still had some mercenaries quartered in Tunis, and was also able to deploy the mercenaries still in Sicily and to hire fresh troops. Initially neither side had any clear advantage, and a mercenary siege of Utica, the largest Carthaginian city after Carthage itself, resulted in the Battle of the Bagradas River which ended with a Carthaginian victory. The conflict escalated when the mercenary leadership tortured and killed its Carthaginian prisoners and in response the Carthaginians committed similar actions. Gesco and 700 of his men had their arms and legs broken, their hands and feet cut off, and were thrown into a pit to die, according to Will Durant. These atrocities were intended to prevent any possibility of a negotiated settlement, contributing to the "most impious war in history."
Hamilcar Barca, general from the campaigns in Sicily, was given supreme command, and eventually defeated the rebels in 237 BC, but the conduct of the war was barbaric even by the standards of the time. Polybius called it a "truceless war", without any concept of rules of warfare and exceeding all other conflicts in cruelty, ending only with the total annihilation of one of the opponents.
The seizure of Sardinia and the outrageous extra indemnity fuelled resentment in Carthage. The loss of Sardinia also encouraged Hamilcar, together with his son-in-law Hasdrubal and his son Hannibal to establish a power base in Hispania, outside Rome's sphere of influence, which later became the source of wealth and manpower for Hannibal's initial campaigns in the Second Punic War.