The Mercenary War, or the Libyan War, was fought in Carthage between 240-238 BC and represents the struggle of the Carthaginian authorities with their own mutinous mercenary army and the Libyans who joined them.
The revolt began immediately after the end of the First Punic War. The costs of war and the indemnity paid to Rome led to Carthage unable to pay off 20,000 mercenaries. Under the terms of the peace treaty between Carthage and Rome, concluded in 241 BC, the Carthaginians were to withdraw all the troops from Sicily.
Military Operations
In 240 BC, an uprising began, which lasted about three years and almost ended in the death of the Carthaginian state. It began with an attack of mercenaries on the leader Giskon and his soldiers. He was captured, and the money he had brought was looted. Libyans almost unanimously supported the uprising.
In total, about 70,000 Libyans, as well as 2,000 Numidians led by the Numidian prince Naravas,  joined the army of the insurgents. So the usual soldiers’ rebellion of mercenaries turned into a people’s liberation war of the Libyan people.  To combat it, Carthage had to create a new army of its own citizens, who had to re-equip and train. Carthage was able to do this because of excellent procedures and infrastructure.
Hamilcar was able to inflict several defeats on the insurgents, the first of which was the defeat of the army of Spendia at the Bagrada River. This was facilitated by the transition to the Carthage side of the Numidians led by Narawas. Hamilcar treated prisoners extremely gently.
However, the leaders of the insurrection, fearing that the amnesty would entail a split among the rebels and the mass transfer of mercenaries to the side of Carthage, did the opposite; they cruelly executed 700 Carthaginian prisoners. Moreover, the insurgents declared that all Carthaginians who were captured would be executed, and all the Carthaginian allies who were captured were threatened with cutting off their hands. Such cruelty led to Hamilcar becoming merciless to rebel mercenaries.
The cities of Utica and Hippakrit voluntarily moved to the side of the insurgents. Utica even asked the Roman Senate to accept it into the system of Roman unions. However, Rome not only refused to accept this offer but helpd the Carthaginians by organizing the supply of food to Carthage. Carthage was even allowed to recruit mercenaries in Italy.
The combined army of mercenaries besieged Carthage, but Hamilcar struck blows on their supply lines and forced the rebels to retreat and lift the siege. Nevertheless, he still had a smaller army at his command than the insurgents, and he had to act very carefully, avoiding an open confrontation.
A turning point in the war came in 238 BC when Hamilcar managed to lure the bulk of the forces of insurgent mercenaries – 50,000 – in the Pila canyon and there besieged them. As a result, the insurgents began to slowly die of hunger and soon resorted to cannibalism. Carthaginians released the leaders of the insurgents from the gorge to participate in negotiations but took them prisoner. The remainder of the army tried to escape from the gorge but was massacred by the Carthaginians. Their leaders were crucified on crosses under the walls of Tunet, where the only remaining rebel force, commanded by Mato, was besieged.
The commander of the besieging Tunet Carthaginian troops was Hannibal. However, Mato, taking advantage of Hannibal’s carelessness, attacked the army of Hannibal and captured him and crucified him on the very cross where Spendius died. Along with him, another 30 noble Carthaginians were killed.
This defeat caused Carthage to declare a general mobilization and all citizens capable of carrying arms were enrolled in the army. This extraordinary measure soon brought fruit: Hamilcar, to whose aid reinforcements arrived from Carthage, defeated the army of Libyan rebels. Mato was taken prisoner, and the Carthaginians beat him to death on the streets of the city during the triumphal march of the Carthaginian army. In 238 BC, the Libyan war ended, which lasted almost three years and four months.
The Revolt in Sardinia
Simultaneously with the insurgency in the African possessions of Carthage in 240 BC, there was a smaller uprising of mercenaries in Sardinia. Reasonably fearing the brutality of the reprisals of the Carthaginians, the rebels suggested that Rome annex the island. Rome denied them.
Then, in 238 BC, the broken and frightened Sardinian rebels appealed for protection from Rome, again offering Sardinia. This time the Roman Senate agreed with their proposal and began to prepare an expedition for the occupation of Sardinia and Corsica. In 237 BC, Carthage, suppressing the uprising in its African possessions, began to equip the navy to regain these islands. The Romans used these preparations as a pretext to declare war on Carthage, stating that the Carthaginians had violated the peace and their military preparations were directed against Rome.
Extremely weakened both as a result of the First Punic War and the insurrection of mercenaries, Carthage had no capability for another war and had to immediately surrender without a fight. Thus, taking advantage of the weakness of the defeated enemy, Rome seized two large islands, of enormous strategic and economic significance, by the mere threat of war. Carthage was forced to make peace, renouncing all claims to Sardinia and Corsica that had passed to Rome, as well as pay a humiliating additional contribution of 1,200 talents to reimburse Roman military expenses.
Effects
The loss of Sardinia, along with the loss of Sicily after the First Punic War, also meant that trade, the traditional source of Carthage’s wealth, was seriously reduced. This caused the Carthaginians to seek new sources of wealth and led Hamilcar, together with his son-in-law Hasdrubal and son Hannibal, to plan to conquer new possessions on the Iberian Peninsula, outside the sphere of influence of Rome. This country subsequently became a source of huge wealth and significant military contingents for Hannibal at the beginning of the Second Punic War.
Sources:
- Polybius . Universal History
- Diodorus of Sicily