This alliance was strengthened during a visit by Juba to Rome when Julius Caesar insulted him by pulling on his beard during a trial wherein Caesar was defending his client against Juba's father and still further in 50 BC when the tribune Gaius Scribonius Curio openly proposed that Numidia should be sold privately.

Encouraged by this success, Curio acted on what proved to be faulty intelligence and attacked what he believed to be a detachment of Juba's army.

Juba immediately left the command of his kingdom's defence with Saburra and joined Scipio with three legions, approximately 15,000 light infantry, 1,000 cavalry, and 30 elephants for the Battle of Thapsus.

Having fled with the Roman general Marcus Petreius and finding their retreat cut off, they made a suicide pact and engaged in one on one combat.

Sources vary on the outcome, but it is most likely that Petreius killed Juba and then committed suicide with the assistance of a slave.