In the years following the Battle of Zama and the defeat of Hannibal in the Second Punic War, Rome and Carthage maintained an adversarial conqueror and conquered relationship. Rome continued to expand in the east, while dealing with problems in their newly acquired Spanish territories. Rome also continued to support their Numidian ally Masinissa, even discreetly encouraging invasion of Carthaginian lands while Carthage was left to beg for Roman intervention. Immediately after the Second Punic War, Hannibal Barca maintained his power in Carthage and did considerable work to clean up corruption and economic problems within the nation, but his enmity with Rome would eventually force his ouster. By the time the Romans were going to war with Anthiochus III of Syria, Hannibal had been forced into exile and joined this new Roman enemy.
Hannibal's departure from Carthage did little to endear them to the untrusting and vengeful Romans. Terms of the treaty with Rome forced Carthage to give up its army, and the resulting financial savings were considerable. The regime that replaced Hannibal attempted to use this new found economic fortune to make for peaceful relations with their old nemesis, but to no avail. Attempts to pay off their annual tribute in one lump sum were denied (to prevent the release of the obligation that Carthage would continue to owe to Rome), and grain shipments meant as gifts to help the Romans in Greece and Macedonia were received and paid for in full by the Senate. The Romans clearly didn't want any relationship that might be seen as requiring reciprocal favors.
Masinissa and his large Numidian army made a regular pattern of incursions against Carthage. Major efforts were launched about every decade since the end of the Second Punic War. The years 193, 182, 172, and 162 BC all played host to Numidian advances. At first, despite Roman bias towards Masinissa, obligations elsewhere led them to be slightly less one sided against Carthage, but by the 170's and 160's BC, this attitude took an abrupt about face. The invasion of 162 BC and resulting requests for help from Carthage were ignored. Masinissa was allowed to keep his gains, and relations soured even further. The next decade, the 150's BC, saw increased Numidian activity and frequent embassies from Carthage to Rome with each request for aid being denied in turn. Yet despite Rome always favoring Masinissa's cause, no effort was made to declare war themselves, leaving the policing of Carthaginian resurgence to their Numidian allies. While Carthage remained a troubling worry for Rome ever since Hannibal, there were enough Senators in Rome who wanted peace, or a real justification for war, before allowing the pro-war Senators to have their way.
Repeated Numidian raids brought the situation to a head in the late 150's BC. By 153 BC, another Carthaginian complaint sent a Roman delegation (essentially a spy mission) to Carthage, headed by Cato the Elder. In investigating the claims of injustice, the Romans inspected all areas of Carthaginian territory. Cato, in particular, was disturbed at the apparent wealth of Carthage and the prosperity of its countryside. Upon returning to Rome, Cato made it his mission to inspire the Romans to war against Carthage once again to prevent a possible rebirth of Carthaginian power.
There is a story of Cato making a speech before the Senate where he dramatized the danger of Carthage to Rome. Shaking the folds of his toga some large African figs fell on the ground as if by accident. As the Senators admired the figs size and natural beauty, Cato when on to explain that the origin of these magnificent specimens was only 3 days away by sail. It is likely that Cato meant to show that the terms of the Roman peace treaty did nothing to hamper the newfound economic prosperity of Carthage. In just a short time, Carthage was building to a position to again be a threat to Rome. Whatever the angle meant by this display, Cato made it his cause to inspire war. From this point on, until war was finally declared, Cato uttered the famous line after every comment in the Forum, "ceterum censeo delendam esse Carthaginem (commonly referred to as Carthago delende est) which translates as "Besides which, my opinion is that Carthage must be destroyed". It has been recorded that he used the line, at times, after every sentence he spoke, regardless of the subject matter of his statements.
Roman lack of response to Carthaginian concerns led to a change in their government. A party in opposition to Roman appeasement had come to power by 151 BC. It was at this time that Masinissa laid siege to a Carthaginian town, and the new government decided its attempts to get Roman intervention had been exhausted. An army of 25,000 raw recruits was raised and it attempted to lift the siege. The Numidians crushed the inexperienced army, but worse yet, a military tribune, Publius Cornelius Scipio Aemilianus (grandson of Scipio Africanus through adoption) was there to witness the battle. Sent from Spain to arrange for the delivery of some war elephants from Masinissa, he just happened to be on hand for the slaughter. A report issued on the affair to Rome was interpreted as a Carthaginian violation of their treaty rather than a description of a great Numidian victory. As a result the Carthaginians were stripped of their ability to defend themselves and were not allowed to raise an army or conduct war without Roman approval and conditions were moving ever closer to a state of war.
New attempts by Carthage to appease the Romans were ignored and the Carthaginian city of Utica offered itself in unconditional surrender to Rome before war even broke out. Hopelessness reigned supreme for the Carthaginians with good reason. By 149 BC, more attempts by African envoys were proved to be futile. Rome had finally declared war and sent two consular armies of 80,000 infantry and 4,000 cavalry from Sicily to Utica, only 10 miles from the Carthage itself. Once these armies arrived in Utica, a panicked populace complied with any Roman demand including the surrender of their arms, over 200,000 sets of armor and 2,000 siege weapons. Pushing the limits, the Consuls seemed unable to goad Carthage into war, but one final demand finally inspired the enemy. The Carthaginians were told to abandon the city of Carthage so it could be razed as punishment for disobedience, but the populous was free to leave and settle anywhere within existing Carthaginian territory so long as it was at least 10 miles from the sea. Carthage finally woke up, realizing that war was the only option, and that since failure to resist seemed to lead to destruction anyway, they prepared to meet their invaders.
While Carthage prepared for a siege, the Roman army suffered greatly from disease. Badly hampered by losses, they were unable to attack Carthage before the Carthaginians were ready. Minor attacks on towns outside of the city were conducted, but little was really accomplished. It wasn't until 147 BC that the Senate felt a change was in order. Since the campaigns of Scipio Africanus and his victory over Hannibal at Zama, it was believed that Carthage couldn't be defeated without a Scipio in command, and the man who had first reported the Carthaginian breaking of the treaty was elected Consul. Public Cornelius Scipio Aemilianus took command and immediately made strides. Forcing the enemy to withdraw within the city of Carthage, he blockaded the harbor to prevent supply and laid waste to the countryside. By the winter of 147/146 BC, the Romans occupied the outskirts of Carthage and were prepared for a final attack.
The spring of 146 BC opened with an assault on the city. 6 days of brutal street fighting was a testament to both dire Carthaginian resistance and determined Roman resolve. First capturing the walls, then surrounding the citadel, the Romans were free to wreak havoc on the civilian population. Before the final Carthaginian surrender, a city of some 700,000 people was reduced to as few as 50,000 defenders. Upon finally giving up, these remaining forces were rounded up and sold into slavery. In the aftermath, despite Scipio's objections, he was ordered to raze the city. Taking every bit of plunder they could, the Romans destroyed the harbor, demolished all large stone structures and burned the city for 10 days. (Despite popular opinion, the salting of the land afterward to prevent repopulation was a story introduced long after the fact and may not have happened at all.) Carthage and its status as a power of the ancient world was finally destroyed, and even the city itself would not be successfully rebuilt ntil the reign of Augustus some 150 years later.
Carthaginian territory along the coast and slightly into the interior was organized as the Roman province of Africa. Numidia, under Masinissa, was allowed independence as a client kingdom. Roman hegemony now spread from Africa in the south, Spain to the west and Asia Minor to the east. While Rome was the indisputable master of the western world, her rapid growth, accompanied with opportunity for corruption and economic disparity among the classes would lead to new problems for the empire. Additionally, the massive amount of slave labor imported from Africa, Spain and the east created a new economy dependency on continuing slavery. These conditions would ultimately be major factors in the crumbling of the Roman political system and the terrible strife between the Patricians, Equestrian order and the common Plebes. With the defeat of Carthage Rome inherited an empire but it ultimately set about the fall of its own Republic.