 After the Republicans were defeated at the Battle of Philippi, Labienus joined the Parthians.Despite Rome's internal turmoil during the time, the Parthians did not immediately benefit from the power vacuum in the East due to Orodes II's reluctance despite Labienus' urgings to the contrary.In the summer of 41 BC, Antony, to reassert Roman power in the East, conquered Palmyra on the Roman-Parthian border.