After a Roman army under Manilius landed in Africa in 149 BC, Carthage surrendered and handed over hostages and arms. However, the Romans demanded the complete destruction of the city, and surprisingly - to the Romans, though perhaps less surprising to us - the city refused, the faction advocating submission overturned by one in favor of defense.
The Carthaginians manned the walls and defied the Romans, a situation which lasted for two years due to poor Roman commanders. Then the Romans elected the young but popular Scipio Aemilianus as consul, a special law being passed to lift the age restriction. Scipio restored discipline, defeated the Carthaginians in a field battle, and besieged the city closely, constructing a mole to block the harbor.
In the spring of 146 the Romans broke through the city wall and captured the city after house-to-house fighting. An estimated 50,000 surviving inhabitants were sold into slavery, the city leveled and the site sown with salt.