Juba I was the last independent king of Numidia, the great-grandson of Massinissa and the father of Juba II. He came to the throne around 60 BCE and ruled the truncated Numidian client kingdom that had survived the Jugurthine War, with his capital at Cirta. His reign coincided with the late Roman Republic and the civil war between Caesar and Pompey, in which Juba allied himself decisively with the Pompeian side.
The decision was rooted in an earlier confrontation with Caesar. As a young man visiting Rome on an embassy from his father Hiempsal II, Juba had been publicly insulted by Caesar, who had pulled his beard during a court hearing — a humiliation Juba did not forget. When the civil war broke out, Juba committed Numidian military and financial resources to the Pompeian cause, contributing decisive elephant cavalry at the engagements at Utica and Thapsus.
The Pompeian defeat at Thapsus in April 46 BCE ended Juba's kingdom. Pursued by Caesarian forces and unable to find refuge, Juba and the Roman Pompeian commander Marcus Petreius killed each other in a ritualised duel after a final dinner at Zama. Caesar annexed the Numidian territory as the new Roman province of Africa Nova.
Juba's infant son Juba II was carried to Rome as a captive and paraded in Caesar's African triumph. Raised at the household of Octavian, Juba II would later be installed by Augustus as king of Mauretania and become one of the most learned figures of the Augustan court. The line from Massinissa through Hiempsal II and Juba I to Juba II is the principal genealogy of pre-imperial Berber royalty preserved in the classical sources.