The Battle of Cirta was fought in 203 BC between an army of largely Masaesyli Numidians commanded by their king Syphax and a force of mainly Massylii Numidians led by Masinissa, who was supported by an unknown number of Romans under the legate Gaius Laelius. It took place somewhere to the east of the city of Cirta (modern Constantine) and was part of the Second Punic War. The numbers engaged on each side and the casualties suffered are not known.
During the Second Punic War (218 to 201 BC) the Roman general Publius Cornelius Scipio expelled the Carthaginians from Iberia (modern Spain and Portugal) in 206 BC. Scipio then contacted several Numidian leaders, who ruled North African territories to the west of those controlled by Carthage. Scipio failed to win over the Masaesyli Numidian king Syphax, who had previously fought the Carthaginians; but did persuade the Massylii Numidian prince Masinissa, whom he had fought against in Iberia, to defect to the Roman cause. Encouraged by the Carthaginians, Syphax overran Masinissa's lands and drove him into exile. In 204 BC the Romans, led by Scipio, invaded North Africa. Masinissa rode to support them with a small force. Syphax brought a large army to assist Hasdrubal Gisco's Carthaginians. After several months Scipio inflicted a heavy defeat on Hasdrubal and Syphax at the battle of Utica. The pair regathered their forces but were defeated again at the battle of the Great Plains. Masinissa's forces fought alongside the Romans in both battles.
Syphax fled back to his capital, Cirta, and hastily raised a new army. Masinissa pursued, together with a Roman force under Scipio's second-in-command, Laelius. Masinissa and Laelius pressed for an immediate battle, but when they achieved this Syphax's troops initially had the better of the fighting. As increasing numbers of Roman infantry entered the fray, Syphax's men were first held off and then broke and fled. Syphax was captured. Masinissa took his cavalry to Cirta, which surrendered when Syphax was paraded in chains. The following year Scipio defeated Hannibal at the battle of Zama, which effectively ended the war. Masinissa was installed as king of all of Numidia.