He is described in sources as Punicus's lieutenant, which would explain the quick way he was promoted to leader after the latter's death. Caesarus might have previously accompanied him during his service as a mercenary for Phoenician or Carthaginian territories in the south of the Iberian Peninsula. In 155 BC, Punicus provoked the Lusitanians and Vettones into revolting and pillaging the Roman colonies, but after being killed in 153 BC, he was relieved by Caesarus. The new chieftain had his first major battle in Hispania Baetica against the forces of Roman Praetor Lucius Mummius. Although the Roman forces were initially successful, obliging the Lusitanians to fall back and abandon their plunder, the Roman forces became disorganised in the chase, which Caesarus capitalised on to counter-attack. Mummius was defeated in the ensuing battle with 9,000 of his men dying, allowing the Lusitanians to regain their spoils and also capture many of the Romans' weapons and standards. It has been speculated the whole sequence might have been a deliberate ruse by the Lusitanians. In any case, Caesarus then paraded mockingly with the Roman standards through the Iberian peninsula. Caesarus's forces faced Mummius again later, after the latter had remained in fortified positions training his army. This time Mummius won, recovering part of the lost plunder. Caesarus is not mentioned as being among the Lusitanians, making his ultimate fate unknown. Shortly after, another Lusitanian contingent from adjacent lands would join the war, led by the warlordCaucenus.
Etymology
The meaning of the name Kaisaro is disputed, though it is believed it has a Phoenician root, bringing the possibility it was a title gained during his military experience in Phoenician territories. It might derive from the wordksr, related to the Carthaginian god Kusor, or alternatively from kysr, translating as "elephant". Departing from the Phoenician thesis, it might come as well from the Celtic, most specifically the wordsgaesi or gaesum, similar to the Celtic-Germanic name Caesorix.
In film and television
The Spanish televisionseriesHispania, La Leyenda features Caesarus as the chief of Viriathus's home village. He is played by Lluís Marco.