In 149 BC, a Carthaginian army under Hasdrubal marched against King Masinissa of Numidia. This action violated the peace treaty signed in 201 BC that forbade Carthage from waging war without Rome's permission. The campaign ended in disaster at the Battle of Oroscopa where the Carthaginian forces surrendered. Anti-Carthaginian factions within the Roman Senate used this illicit military action as a pretext to prepare a punitive expedition. Cato, a senior senator known for ending his speeches with the phrase "Carthage must be destroyed," had long advocated for further military action against the city-state. In contrast, Scipio Nasica argued that fear of a strong enemy like Carthage kept the common people in check and avoided social division. Despite Carthage paying off its indemnity in 151 BC and prospering economically, Rome declared war after the large North African port city of Utica went over to them. The Senate and People's Assembly of Rome then demanded that Carthage hand over all weaponry.
Siege Engineering Tactics
Scipio Aemilianus built an immense mole to cut off access to the harbour via blockade runners. The Carthaginians responded by cutting a new channel from their harbour to the sea. They had built a new fleet and once the channel was complete, they sailed out taking the Romans by surprise. In the ensuing Battle of the Port of Carthage many ships were trapped against the city's sea wall and sunk or captured. The Romans now attempted to advance against the Carthaginian defences in the harbour area eventually gaining control of the quay. Over several months they constructed a brick structure as high as the city wall which enabled up to 4,000 Romans to fire onto the Carthaginian ramparts from short range. This feature allowed Roman forces to dominate the city walls directly. Once this construction was complete Scipio detached a large force and led it against the Carthaginian field army at Nepheris. The town of Nepheris surrendered after three weeks and most fortified positions still holding out in Carthage's hinterland opened their gates.