Aretas III was king of the Nabataean kingdom from 87 to 62 BCE. Aretas ascended to the throne upon the death of his father, Obetas I, in 87 BCE. During his reign, he extended his kingdom to cover what now forms the northern area of Jordan, the south of Syria, and part of Saudi Arabia. Probably the greatest of Aretas' conquests was that of Damascus, which secured his country's place as a serious political power of its time. Nabataea reached its greatest territorial extent under Aretas' leadership.
In 67 BCE, Hyrcanus II ascended to the throne of Judea. Scarcely three months later, his younger brother Aristobulus II incited a rebellion, successfully leading the uprising to overthrow Hyrcanus and take the offices of both King and High Priest. Hyrcanus was confined to Jerusalem, where he would continue to receive revenues of the latter office. However, fearing for his life, he fled to Petra and allied himself with Aretas, who agreed to support Hyrcanus after receiving the promise of having the Arabian towns taken by the Hasmoneans returned to Nabataea by Hyrcanus' chief advisor, Antipater the Idumaean.
Aretas advanced towards Jerusalem at the head of 50,000 men, besieging the city for several months. Eventually, Aristobulus bribed Marcus Aemilius Scaurus, deputy of the Roman general Gnaeus Pompeius Magnus. Scaurus ordered Aretas to withdraw his army, which then suffered a crushing defeat at the hands of Aristobulus on the journey back to Nabatea.
Despite the compliance of Aretas, in 62 BCE Scaurus marched on Petra. However, a combination of the rough terrain, low supplies, and an opportunity for gain in Pontus following the suicide of Mithridates VI obliged Scaurus to send Hyrcanus, now high priest and ethnarch (but not King) of Judea, to barter for peace with Aretas. The siege was lifted in exchange for several hundred talents of silver (to Scaurus himself) and recognition of Roman supremacy over Nabatea. Aretas would retain all Nabataean territory and possessions, becoming a vassal of the Roman Empire.