The Masinissa helped to the Numidians during the war and defeated Carthage.

In antiquity Algeria was known as the Kingdom of Numidia, its people were called Numidians. This land has been populated since 10,000BC

Carthage did not defeat Numidia. When she raised an army to defend herself, she was defeated by the Numidians. Then the Romans declared war and destroyed Carthage.

The Romans had many foes. Such as the Gauls, Germans, Britons, Carthaginians, Persians, Huns, Numidians, Egyptians, the Greek city states and many small barbarians kingdoms like the Visigoths and Vandals.

There was a faction, led by Cato the Elder, in Rome which favoured the destruction of Carthage. Cato usually finished his speeches in the senate with "furthermore, it is my opinion that Carthage must be destroyed." Senator Publius Cornelius Scipio Nasica Corculum, supported a policy of not destroying Carthage, and usually won the debate.

One Cato's faction concerns was the prosperity which the city regained though the savings incurred not having to maintain an army as the peace treaty with Rome had included demilitarisation. This faction was worried about a prosperous Carthage could become a threat again.

After having she finished paying for her 50-year annual payments as war indemnity, Carthage considered the treaty completed. She raised an army to confront their neighbours, the Numidians, who were raiding and seizing cities in her territory. A report that Carthage had fought a battle against the Numidians was interpreted as a breach of the treaty. The fact that the report said that the new Carthaginian army was inexperienced and inefficient and that it had been defeated was overlooked.

The reality was that Carthage needed to defend herself and that Rome ignored the actions of the Numidians or, when asked to arbitrate, she ruled in favour of the Numidians. However, the war part gained the upper hand and war was declared.

It has also been speculated that there was an interest in Carthage's highly productive agricultural land.