Monobazus II was the son of Queen Helena of Adiabene and King Monobazus I. He is known as Monobaz in the Babylonian Talmud. Like his younger brother Izates bar Monobazus and his mother, Monobazus became a convert to Judaism. He ruled as king of Adiabene after the death of his brother Izates around 55 CE. The date of his death is unknown but he is known to have been alive and on the throne during the First Jewish-Roman War, when he gave aid to the Jewish rebels against the Roman Empire. Two 'kinsmen' of Monobazus, Monobazus and Kenedaeus, fought on the side of the Jews in the battle against Cestius. The 'sons and brothers of Izates the king' were taken hostage to Rome after the war.