Following the Battle of Mount Labus in 209 BC, Antiochus III invaded Hyrcania and seized the cities of Tambrax and Syrinx, forcing Arsaces II, who was permitted to continue his rule over Hyrcania and Parthia, to become a vassal of the Seleucid Empire. During the siege of Syrinx, when the wall was breached, the garrison slaughtered the Greek inhabitants and attempted to flee. Arsaces II may have reasserted his independence in 189 BC, following Antiochus' defeat at the hands of the Romans at the Battle of Magnesia in 190 BC. During the reign of Antiochus IV, in the late 2nd century BC, Hyrcania still formed part of the Seleucid Empire. After Mithridates' conquest of Media in 148 BC, Hyrcanians launched an unsuccessful revolt, which was crushed by Mithridates shortly afterwards. Hyrcania served as a royal retreat and Mithridates retired there in 141 BC. In 139 BC, Demetrius II launched an invasion of the Arsacid Empire only to be defeated and captured, following which he was provided a princely residence in Hyrcania and married to Rhodogune, daughter of Mithridates. In 129 BC, the Saka tribes invaded and pillaged Hyrcania, alongside other eastern provinces, and defeated and killed two successive Arsacid kings. Soon after his ascension to the throne in 124 BC, Mithridates II, recovered Hyrcania and re-established Arsacid control.