Battle of Mount Gindarus by a Roman force. His death spurred a succession crisis in which Orodes II (), deeply afflicted by the death of his favourite son, relinquished the throne to his other son Phraates IV. Orodes II died soon afterwards. His cause of death is uncertain. According to Cassius Dio, he had either died of grief due to Pacorus' death, or of old age. Plutarch, however, states that Orodes was murdered by Phraates IV. Fearing that his position might become endangered, Phraates IV executed all his half-brothers–the sons of Orodes and his Commagenian wife Laodice, partially due to their maternal descent being greater than that of his own. Laodice was probably killed as well. Phraates IV also had supporters of his brothers and his own opponents sent into exile; one of them, Monaeses, a Parthian nobleman who had distinguished himself as a military leader under Orodes II, fled to Syria, where he took refuge with the Roman triumvir Mark Antony. There Monaeses urged him to attack Parthia, and promised him to spearhead the troops and conquer the empire without any difficulties. Antony granted Monaeses three cities—Larissa, Hierapolis and Arethusa, and promised him the Parthian throne. Around the same time, Antony had restored Roman rule in Jerusalem, and executed the Parthian puppet king Antigonus II Mattathias, who was succeeded by Herod the Great. The relations between Parthia and Armenia had also been damaged, due to the death of Pacorus I (who was married into the Armenian royal house) and Phraates IV's treatment of his brothers and some of the nobility, which upset the Armenians. The Parthians took the defection of Monaeses very serious, and as a result Phraates IV invited Monaeses back to the country and reconciled with him. War with Mark Antony The following year, when Antony marched to Theodosiopolis, Artavasdes II of Armenia defected to the Roman side by sending Antony additional troops. Antony invaded Media Atropatene, then ruled by Parthia's ally Artavasdes I, with the intention of seizing the capital Praaspa, the location of which is now unknown. However, Phraates IV ambushed Antony's rear detachment, destroying a giant battering ram meant for the siege of Praaspa; after this, Artavasdes II abandoned Antony's forces. The Parthians pursued and harassed Antony's army as it fled to Armenia. Eventually, the greatly weakened force reached Syria. The defeat of Antony, along with that of Crassus at Carrhae in 53 BC,