The Hasmonean Civil War was a significant conflict in Jewish history that led to the loss of Jewish independence. It began as a power struggle between two brothers, Hyrcanus and Aristobulus, who vied for the Hasmonean Jewish Crown. Aristobulus, the younger and more ambitious of the two, used his connections to take control of walled cities and hired mercenaries to declare himself king while their mother, Alexandra, was still alive. This action resulted in a confrontation between the two brothers and a period of civil strife.

Nabataean involvement further complicated the conflict when Antipater the Idumean convinced Hyrcanus to seek support from Aretas III, the king of the Nabataeans. Hyrcanus made a deal with Aretas, offering to return 12 cities to the Nabataeans in exchange for military assistance. With the support of Nabataean forces, Hyrcanus confronted Aristobulus, leading to a siege of Jerusalem.

Roman involvement ultimately determined the outcome of the conflict. Both Hyrcanus and Aristobulus sought support from Roman officials, but Pompey, a Roman general, ultimately sided with Hyrcanus. He laid siege to Jerusalem, and after a long and intense battle, Pompey's forces managed to breach the city's defenses, leading to the capture of Jerusalem.

This event marked the end of the Hasmonean dynasty's independence, as Pompey reinstated Hyrcanus as High Priest but stripped him of his royal title, establishing Roman influence over Judea. Judea remained autonomous but was obliged to pay tribute and dependent on the Roman administration in Syria. The kingdom was dismembered; it was forced to relinquish the coastal plain, depriving it of access to the Mediterranean, as well as parts of Idumea and Samaria. Several Hellenistic cities were granted autonomy to form the Decapolis, leaving the state greatly diminished.