 Complete the following phrase:  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 