The Mercenary War, or Truceless War, was a brutal conflict fought between Carthage and its mutinous soldiers from 241 to 237 BCE, during a lull in the Punic Wars. When Carthage's mercenary soldiers were denied the payment that they had been promised, they revolted, leading to a large-scale rebellion supported by several North African settlements. The Carthaginians initially fared poorly against the rebels, but their luck turned around under the generalship of Hamilcar Barca (circa 275 to 228 BCE), who scored several decisive victories. Though Carthage ultimately won the war, it was left in a weakened condition, allowing Rome to take advantage by seizing control of Sardinia and Corsica, thereby paving the way for the Second Punic War (218 to 201 BCE).

In 241 BCE, the First Punic War between Rome and Carthage finally came to an end. After 23 years of perpetual warfare, both rival Mediterranean powers were war-weary and exhausted, but it was the Carthaginian spirit that broke first. No longer able to feed or supply its armies, Carthage was forced to agree to a disadvantageous peace treaty that included ceding control of Sicily to Rome, releasing all prisoners of war, and paying a massive war indemnity over the course of the next decade. The Carthaginian Senate instructed Hamilcar Barca, commander of its forces in Sicily, to finalize the treaty with the Roman Republic before seeing to the demobilization of his army. Hamilcar, however, was disgusted by the treaty, which he viewed as not only unnecessary but humiliating. Rather than follow through with his orders, he resigned the command of his army and left Sicily in grief and rage. It therefore fell to his lieutenant, Gisco, to take charge and oversee the demobilization.

Gisco found himself responsible for an army of 20,000 men, most of whom were foreign mercenaries. It had long been customary in Carthaginian warfare to employ foreigners in its armies, as citizens were typically only expected to fight when the city itself was in danger. These mercenaries came from all corners of the Mediterranean world and included Libyans, Numidians, Iberians, Gauls, Ligurians, and Sicilian Greeks. By this point, most of them were veteran soldiers who had served in Carthage's armies for years, and all of them expected that, now that the war was over, they would collect the several years' back pay that they were owed before heading home. Gisco realized the logistical headache of letting all 20,000 men go back at once, so he decided to divide the army into smaller detachments and send them to Carthage one by one. That way, the Carthaginian government could pay each contingent what it was due and send it back to its homeland before the arrival of the next one, which would avoid putting undue strain on the treasury and would avoid concentrating too many mercenaries in the city at any one time.

When the first group arrived in Carthage, however, they found that their benefactors were unable to pay them. Two decades of war had nearly sucked the Carthaginian treasury dry, and what money was left would be needed to pay the indemnity to Rome. The Carthaginian officials, therefore, decided to negotiate with the mercenaries and try to get them to accept a lower payment. Before doing so, they decided to wait until all the mercenaries had come over from Sicily, housing the mercenaries who had already come over within the walls of Carthage itself. This proved to be a bad idea. The mercenaries quickly became unruly, with the Greek historian Polybius commenting that crimes were committed "in broad daylight as well as by night" (1.63). To preserve law and order inside their city, the Carthaginians relocated the mercenaries to the town of Sicca (modern El Kef), 110 miles (177 km) away. They provided each mercenary with enough gold to meet his immediate needs and promised that the rest of the payment was forthcoming.

At Sicca, the last vestiges of military discipline broke down as the mercenaries were given over to inactivity and boredom. With little else to do, each man calculated the exact amount of money that he was owed. It was amidst this atmosphere of restlessness and heightened expectations that the camp was finally visited by Hanno, the Carthaginian general in charge of North Africa. But rather than doling out the expected payments, Hanno spoke vaguely about Carthage's economic troubles and offered to pay the mercenaries at a rate much lower than they anticipated. Over the next few days, Hanno continued to speak with mercenary leaders, but due to the many different languages spoken throughout the camp, he often had to rely on translators, leading his words to become distorted. It was not long before the mercenaries had had enough. Packing up their belongings, they marched toward Carthage, setting up camp at Tunis, only 14 miles (22 km) south of the great city. They were determined to get what they were owed – one way or another.

When the citizens of Carthage awoke to find a mercenary army on their doorstep, they panicked. With no army available to defend the city, the Carthaginian Senate sent delegations to the mercenary camp to offer them anything they wanted. Emboldened by this reaction, the mercenaries "kept contriving new demands every day". Once the Carthaginians agreed to hand over the full payment, the mercenaries demanded compensation for the horses they had lost on their march over, as well as the cash equivalent of the highest price that grain had reached during the war. "In short," writes Polybius, "they constantly came up with outrageous new demands, stretching the terms of their agreement to the impossible limits" (1.68). Unable to meet these demands, the Carthaginians decided to call in one of the generals who had led the mercenaries in Sicily to act as a mediator. Since Hamilcar Barca was unacceptable to the mercenaries – they believed he had deserted them when he resigned his command in a rage – the responsibility once again fell to Gisco, who left Sicily and sailed to Tunis with a retinue of officers and several chests filled with money.

Gisco set about de-escalating the situation. He met with the mercenary officers, listened to their grievances, and began making preparations to dole out the money. According to Polybius, this would have been enough to satisfy most of the mercenaries and likely would have resolved the issue, had it not been for a few troublemakers in the mercenary camp. One of these was Mathos, a Libyan who had helped instigate the march to Tunis and now feared reprisals from the Carthaginians once the mercenary army disbanded. Another was Spendius, an escaped Italian slave who had fought bravely in Sicily but now faced the prospect of being returned to his Roman masters and tortured to death. With their lives literally on the line, neither Mathos nor Spendius could afford to make peace with the Carthaginians and began playing into the anxieties of their fellow mercenaries. They appealed to the Libyans, by far the largest nationality represented in the mercenary army, and warned them that once the other groups had been sent home, they would be left behind to suffer the full might of Carthaginian vengeance.

Like every good lie, this contained several grains of truth – in the past, Carthage had cracked down severely on the Libyan people under its control, ruthlessly extracting heavy taxes from them. Fear turned to unrest, which in turn led to mob rule. Whenever any officer or soldier spoke up to challenge the inflammatory comments of Mathos or Spendius, they were set upon by their frenzied followers and stoned to death. Such stonings became so common that the phrase 'Stone him!' in Phoenician became the only words that were universally recognized by everyone in that multilingual army. Before long, no one criticized Mathos or Spendius, whose influence reached such a point that they were being referred to as generals by the mercenaries. Although he was aware of the growing dissent, Gisco refused to leave Tunis, believing it was his duty to resolve the crisis. One day, he was approached by a group of Libyans, who complained that they had not been paid the full amount. Tired of hearing the same complaints, Gisco curtly told them to appeal to 'General Mathos' for their money. For the Libyans, this was the final straw. They seized Gisco and his officers, who were put in chains and thrown in prison. This marked the point of no return, as the mercenaries traversed the camp, capturing any Carthaginians they could find and seizing their property.

Mathos and Spendius immediately dispatched messengers to the Libyan cities and settlements in North Africa – now was the time, they said, to cast off the yoke of Carthaginian rule and recover their liberty. Aside from the cities of Utica and Hippo Acra, lying on the coast northwest of Carthage, most of these settlements joined the revolt, sending provisions, soldiers, and funds to the rebel army. Their forces augmented by an additional 70,000 men, Mathos and Spendius decided to divide and conquer – Mathos was to lay siege to Utica and Hippo Acra, to punish them for not joining the revolt, while Spendius blockaded Carthage itself, cutting it off from grain supply and trapping its garrison within its walls. The Carthaginians, meanwhile, hastily assembled a new army, mustering as many citizens of military age as possible. Command was entrusted to Hanno, the same general who had failed to negotiate with the mercenaries at Sicca. In early 240 BCE, Hanno gathered his army – which included 100 war elephants – and set out to lift the siege of Utica.

Hanno took the rebels by surprise. His soldiers swarmed through their camp while his elephants trampled fleeing rebels underfoot. But once he had chased the mercenaries into the nearby hills, Hanno did not pursue. In the past, defeated rebels did not return to the battlefield but fled all the way home, leaving Hanno to believe his job was done. What he failed to realize was that these were no ordinary rebels but battle-hardened mercenaries familiar with Carthaginian tactics. They regrouped in the hills and waited for the Carthaginian troops to begin celebrating their supposed victory before launching their counterattack. This time, it was the Carthaginians who were taken by surprise; they were soundly defeated, suffering heavy casualties as the rebels sent the survivors running and captured their baggage train. Hanno retreated along with the remnants of his army while the rebels resumed their siege of Utica. Due to his high status, Hanno was not crucified – as was the usual punishment for unsatisfactory Carthaginian generals – but he had been exposed as incompetent, leaving the Carthaginian Senate to look to Hamilcar Barca for their salvation.

Hamilcar quickly raised a new army of 10,000 men and went on the offensive, marching his troops to the Bagradas River (modern Medjerda) north of Carthage. Since the only bridge was defended by a force of rebels under Spendius, Hamilcar had to find another way across. Fortunately for him, his scouts discovered a partially submerged sandbar across the river mouth that his army was able to ford. When Spendius discovered that the Carthaginian army had emerged on his side of the river, he marched to oppose them with 25,000 men, and the two armies clashed at the Battle of the Bagradas River. Sometime during the battle, Hamilcar feigned a retreat, and the overconfident rebels broke ranks to pursue. When the rebels were only 500 yards (450 m) away, the Carthaginian heavy infantry turned and reformed, pinning the mercenaries in place as Hamilcar's massive war elephants plowed into them. Spendius and other survivors managed to escape to Utica, leaving behind 8,000 rebels dead and wounded, and a further 2,000 as prisoners.

Following his victory, Hamilcar could have linked up with Hanno, whose reconstituted army was moving to confront the rebels near Hippo Acra. Instead, he opted to press onward, marching into the countryside to coerce the Libyan settlements there to return to the Carthaginian fold. As he progressed, his army was shadowed by Spendius and a small rebel force, which kept to the foothills to avoid Hamilcar's elephants. Gradually, this rebel force grew in size until it heavily outnumbered the Carthaginian army. Hamilcar moved into the mountains, hoping to draw the rebels into a battle. This backfired, however, when he was outmaneuvered and soon found himself trapped in a valley, hemmed in by rebels on all sides. As the Carthaginians prepared for a fight to the death, they were saved by the intervention of Naravas, a young Numidian leader who had served with Hamilcar in Sicily and admired him greatly. Although he was leading a detachment of rebels, Naravas approached the Carthaginian camp and was allowed an audience with Hamilcar. The two men struck a deal – Naravas would switch sides in exchange for Hamilcar's patronage and a marriage to his daughter. So it was that Naravas brought over 2,000 Numidian cavalrymen to the Carthaginians, tipping the scales. In the ensuing battle, the rebels were once again defeated, losing 10,000 casualties.

Up to this point, Hamilcar had treated captured rebels well, offering to let them join his army or even allowing them safe passage home, on the condition that they never take up arms against Carthage again. This was greatly effective, and by the end of 240 BCE, hundreds of rebel soldiers were deserting to seek the amnesty Hamilcar offered. Spendius and another rebel leader, a Gaul named Autaritus, decided that the only way to prevent future defections was to destroy any goodwill between the two sides. To this end, they grabbed Gisco and 700 other Carthaginian prisoners, marched out to a field, and mutilated them, cutting off their hands, breaking their legs, and castrating them, all before tossing them into a pit and burying them alive. When word of this horrific act reached Hamilcar, he responded in kind by having the rest of his prisoners trampled to death by his elephants. From then on, claims Polybius, neither side showed any mercy to the other, and the fighting took the savage characteristics of a 'truceless war'.

In mid-239 BCE, Hamilcar linked up with Hanno, but the two generals found it impossible to agree on anything. To end the paralysis, a vote was put to the soldiers as to who they wanted for their supreme commander, and Hamilcar was chosen. After the disgraced Hanno left the army, Hamilcar selected an officer named Hannibal as his deputy (not to be confused with the famous Hannibal Barca) and, in early 238 BCE, scoured the rebel supply lines in an attempt to ease the siege of Carthage. Spendius marched to meet this threat with an army of 40,000 men but was outmaneuvered by Hamilcar, who isolated individual rebel detachments and wiped them out one by one. Presently, Hamilcar trapped the rebel army in a mountain pass known as the Saw, where he proceeded to try and starve them out. The rebels quickly ran out of provisions and were forced to resort to cannibalism, consuming first their prisoners and then their slaves. As their desperation reached its peak, Spendius, Autaritus, and eight other rebel leaders went to Hamilcar's camp to discuss terms but were arrested by the Carthaginians on a flimsy pretext. Now leaderless, the rebel army panicked and tried to fight its way out of the Saw but was massacred to a man.

By this point, both Utica and Hippo Acra had switched sides, joining the rebels in order to end the devastating sieges they were subjected to. Hamilcar meant to deal with their treachery but first decided to lay siege to the rebel stronghold of Tunis in late 238 BCE. Since Tunis was difficult to besiege, Hamilcar divided his army, investing the south of the city himself while his deputy Hannibal made camp to the north. When the city refused his initial demands to surrender, Hamilcar had Spendius, Autaritus, and the other prisoners crucified in full view of Tunis' defenders. But while this was intended to scare the rebels into submission, it only hardened their resolve – Mathos, who led the rebels in Tunis, led a nighttime sortie against Hannibal's camp, defeating the Carthaginians and taking Hannibal captive. The rebels tortured Hannibal for a while before crucifying him in the exact spot where Spendius had recently died. After this defeat, Hamilcar was forced to lift the siege and pull back to the north, where he was pressured into reconciling with Hanno. The two generals then led their combined army – some 40,000 strong – to the city of Lepis Parva, where Mathos had fled with the remnants of his army. After a climactic battle, the 30,000-man rebel force was wiped out, and Mathos was taken prisoner. While the other rebel prisoners were crucified on the spot, Mathos was taken back to Carthage, where he was paraded through the city streets before being put to death.

After the death of Mathos, the mutiny quickly unraveled, with most of the rebellious settlements returning to Carthaginian control. Utica and Hippo Acra held out a while longer, fearful of Carthaginian retribution for their late-stage betrayal. However, both cities were already weakened from years of siege, and both surrendered in early 237 BCE. The Mercenary War was over – though Carthage had won, it was left in a weakened condition, something that its rivals were quick to exploit. During the war, Rome had opportunistically seized control of Sardinia and Corsica, both of which were previously under Carthaginian control. This was a blatant disregard of the treaty, but Carthage was too weak to do anything but utter meek protests. Enraged, Hamilcar went to Iberia, where he spent the next several years carving out a semi-autonomous fiefdom for himself. After his death in battle in 228 BCE, control of this fiefdom fell to his son, Hannibal Barca (circa 247 to 181 BCE), who inherited his father's military prowess and hatred for Rome. Thus, the Mercenary War, while a terrible conflict in its own right, helped set the stage for one of the bloodiest wars of the ancient world, the Second Punic War.