Roman – Parthian Wars The Roman – Parthian Wars ( 66 BC – 217 AD ) were a series of conflicts between the Parthian Empire and the Romans . It was the first series of conflicts in what would be 719 years of Roman – Persian Wars . Early incursions by the Roman Republic against Parthia were repulsed , notably at the Battle of Carrhae ( 53 BC ) . During the Roman Liberators ' civil war of the 1st Century BC , the Parthians actively supported Brutus and Cassius , invading Syria , and gaining territories in the Levant . However , the conclusion of the second Roman civil war brought a revival of Roman strength in Western Asia . In 113 AD , the Roman Emperor Trajan made eastern conquests and the defeat of Parthia a strategic priority , and successfully overran the Parthian capital , Ctesiphon , installing Parthamaspates of Parthia as a client ruler . Hadrian , Trajan ' s successor , reversed his predecessor ' s policy , intending to re - establish the Euphrates as the limit of Roman control . However , in the 2nd century , war over Armenia broke out again in 161 , when Vologases IV defeated the Romans there . A Roman counter - attack under Statius Priscus defeated the Parthians in Armenia and installed a favored candidate on the Armenian throne , and an invasion of Mesopotamia culminated in the sack of Ctesiphon in 165 . In 195 , another Roman invasion of Mesopotamia began under the Emperor Septimius Severus , who occupied Seleucia and Babylon , and then sacked Ctesiphon yet again in 197 . Parthia ultimately fell not to the Romans , but to the Sassanids under Ardashir I , who entered Ctesiphon in 226 . Under Ardashir and his successors , Persian - Roman conflict continued between the Sassanid Empire and Rome . Parthia ' s western ambitions . After triumphing in the Seleucid – Parthian wars and annexing large amounts of Seleucid Empire the Parthians began to look west for territory to expand into . Parthian enterprise in the West began in the time of Mithridates I ; during his reign , the Arsacids succeeded in extending their rule into Armenia and Mesopotamia . This was the beginning of an " international role " for the Parthian empire , a phase that also entailed contacts with Rome . Mithridates II conducted unsuccessful negotiations with Sulla for a Roman – Parthian alliance ( c . 105 BC ) . After 90 BC , the Parthian power was diminished by dynastic feuds , while at the same time , Roman power in Anatolia collapsed . Roman – Parthian contact was restored when Lucullus invaded Southern Armenia and defeated Tigranes in 69 BC , however , again no definite agreement was made . Roman Republic vs Parthia . When Pompey took charge of the war in the East , he re - opened negotiations with Phraates III ; they came to an agreement and Roman – Parthian troops invaded Armenia in 66 / 65 BC , but soon a dispute arose over Euphrates boundary between Rome and Parthia . Pompey refused to recognize the title of " King of Kings " for Phraates , and offered arbritation between Tigranes and the Parthian king over Corduene . Finally , Phraates asserted his control over Mesopotamia , except for the western district of Osroene , which became a Roman dependency . In 53 BC , Crassus led an invasion of Mesopotamia , with catastrophic results ; at the Battle of Carrhae , the worst Roman defeat since the Battle of Cannae , Crassus and his son Publius were defeated and killed by a Parthian army under General Surena . The bulk of his force killed or captured ; of 42 , 000 men , about half died , a quarter made it back to Syria , and the remainder became prisoners of war . Rome was humiliated by this defeat , and this was made even worse by the fact that the Parthians had captured several Legionary Eagles . It is also mentioned by Plutarch that the Parthians found the Roman prisoner of war that resembled Crassus the most , dressed him as a woman and paraded him through Parthia for all to see . This , however , could easily be Roman propaganda . Orodes II , with the rest of the Parthian Army , defeated the Armenians and captured their country . However , Surena ' s victory invoked the jealousy of the Parthian king , and he ordered Surena ' s execution . Following Surena ' s death , Orodes II himself took command of the Parthian army and led an unsuccessful military campaign into Syria . The Battle of Carrhae was one the first major battles between the Romans and Parthians . The following year , the Parthians launched raids into Syria , and in 51 BC mounted a major invasion led by the crown prince Pacorus and the general Osaces , but their army was caught in an ambush near Antigonea by the Romans under Cassius and Osaces was killed . During Caesar ' s civil war the Parthians made no move , but maintained relations with Pompey . After his defeat and death , a force under Pacorus came to the aid of the Pompeian general Caecilius Bassus , who was besieged at Apamea Valley by the Caesarian forces . With the civil war over , Julius Caesar elaborated plans for a campaign against Parthia , but his assassination averted the war . During the ensuing Liberators ' civil war , the Parthians actively supported Brutus and Cassius , sending a contingent which fought with them at the Battle of Philippi in 42 BC . After that defeat , the Parthians under Pacorus invaded Roman territory in 40 BC in conjunction with Quintus Labienus , a Roman erstwhile supporter of Brutus and Cassius . They swiftly overran Syria , and defeated Roman forces in the province ; all the cities of the coast , with the exception of Tyre admitted the Parthians . Pacorus then advanced into Hasmonean Judea , overthrowing the Roman client Hyrcanus II and installing his nephew Antigonus ( 40 – 37 BC ) in his place . For a moment , the whole of the Roman East was captured to Parthians . The conclusion of the second Roman civil war was soon to bring about a revival of Roman strength in Western Asia . Meanwhile Mark Antony had already sent Ventidius to oppose Labienus who had invaded Anatolia . Soon Labienius was driven back to Syria by Roman forces , and , though his Parthian allies came to his support , he was defeated , taken prisoner and then put to death . After suffering a further defeat near the Syrian Gates , the Parthians withdrew from Syria . They returned in 38 BC , but were decisively defeated by Ventidius and Pacorus was killed . In Judea , Antigonus was ousted with Roman help by the Idumean Herod in 37 BC . With Roman control of Syria and Judaea restored , Mark Antony led a huge army into Azerbaijan , but his siege train and its escort were isolated and wiped out , while his Armenian allies deserted . Failing to make progress against Parthian positions , the Romans withdrew with heavy casualties . In 33 BC Antony was again in Armenia , contracting an alliance with the Median king against both Octavian , and the Parthians , but other preoccupations obliged him to withdraw , and the whole region passed under Parthian control . Roman Empire vs Parthia . Inconclusive wars . Under the threat of an impending war between the two powers , Gaius Caesar and Phraataces worked out a rough compromise between the two powers in 1 AD . According to the agreement , Parthia undertook to withdraw its forces from Armenia , and to recognize a " de facto " Roman protectorate over the country . Nonetheless , Roman - Persian rivalry over control and influence in Armenia continued unabated for the next several decades . The decision of the Parthian king Artabanus III to place his son , Arsaces , on the vacant Armenian throne triggered a war with Rome in 36 AD . Artabanus III reached an understanding with the Roman general , Lucius Vitellius , renouncing Parthian claims to a sphere of influence in Armenia . A new crisis was triggered in 58 , when the Romans invaded Armenia after the Parthian king Vologases I forcibly installed his brother Tiridates on the throne there . Roman forces under Corbulo overthrew Tiridates and replaced him with a Cappadocian prince . This prompted Parthian retaliation and an inconclusive series of campaigns in Armenia ensued . The war came to an end in 63 , when the Romans agreed to allow Tiridates and his descendants to rule Armenia on condition that they received the kingship from the Roman emperor . Armenia would henceforth be ruled by an Persian dynasty , and despite its nominal allegiance to Rome , it would come under increasing Parthian influence . In the judgment of later generations , " Romans had lost Armenia " , and although the Peace of Rhandeia ushered in a period of relatively peaceful relations that would last for 50 years , Armenia would continue to be a constant bone of contention between the Romans , the Parthians , and their Sassanid successors . As for Corbulo , he was honoured by Nero as the man who had brought this " triumph " to be , but his popularity and influence with the army made him a potential rival . Together with the involvement of his son - in - law Lucius Annius Vinicianus in a foiled plot against Nero in 66 , Corbulo became suspect in the eyes of the emperor In 67 , while journeying in Greece , Nero ordered him to be executed ; upon hearing of this , Corbulo committed suicide . Trajan ' s Parthian War . A new series of wars began in the 2nd century , during which the Romans consistently held the upper hand over Parthia . In 113 , the Roman Emperor Trajan decided that the moment was ripe to resolve the " eastern question " once and for all time by the decisive defeat of Parthia and the annexation of Armenia ; his conquests marked a deliberate change of Roman policy towards Parthia , and a shift of emphasis in the " grand strategy " of the empire . In 114 , Trajan invaded Armenia , annexed it as a Roman province , and killed Parthamasiris who was placed on the Armenian throne by his relative , the king of Parthia , Osroes I . In 115 , the Roman emperor overran northern Mesopotamia and annexed it to Rome as well ; its conquest was deemed necessary , since otherwise the Armenian salient could be cut off by the Parthians from the south . The Romans then captured the Parthian capital , Ctesiphon , before sailing downriver to the Persian Gulf . However , in that year revolts erupted in Palestine , Syria and northern Mesopotamia , while a major Jewish revolt broke out in Roman territory , severely stretching Roman military resources . Trajan failed to take Hatra , which avoided total Parthian defeat . Parthian forces attacked key Roman positions and Roman garrisons at Seleucia , Nisibis and Edessa were evicted by the local populaces . Trajan subdued the rebels in Mesopotamia , installed the Parthian prince Parthamaspates as a client ruler , and withdrew to Syria . Trajan died in 117 , before he could renew the war . Hadrian ' s policy , and further wars of annexation . Trajan ' s successor , Hadrian , promptly reversed his predecessor ' s policy . He decided that it was in Rome ' s interest to re - establish the Euphrates as the limit of its direct control , and willingly returned to the " status quo ante " , surrendering the territories of Armenia , Mesopotamia , and Adiabene back to their previous rulers and client - kings . Once again , at least for another half century , Rome was to avoid active intervention east of the Euphrates . War over Armenia broke out again in 161 , when Vologases I defeated the Romans there , captured Edessa and ravaged Syria . In 163 , a Roman counter - attack under Statius Priscus defeated the Parthians in Armenia and installed a favored candidate on the Armenian throne . The following year Avidius Cassius began an invasion of Mesopotamia , winning battles at Dura - Europos and Seleucia and sacking Ctesiphon in 165 . An epidemic , possibly of smallpox , which was sweeping Parthia at the time now spread to the Roman army , leading to their withdrawal . In 195 , another Roman invasion of Mesopotamia began under the Emperor Septimius Severus , who occupied Seleucia and Babylon , and then sacked Ctesiphon yet again in 197 . These wars led to the Roman acquisition of northern Mesopotamia , as far as the areas around Nisibis and Singara . In 202 , peace was restored and Parthia regained effective control the whole of Mesopotamia . A final war against the Parthians was launched by the emperor Caracalla , who sacked Arbela in 216 , but after his assassination , his successor Macrinus was defeated by the Parthians near Nisibis and had to pay reparations . Rise of the Sassanids . Parthia was finally destroyed by Ardashir I when he entered Ctesiphon in 226 . The Sassanids were more centralized than the Parthian dynasties . Until the Sassanids came to power , the Romans were mostly the aggressors . However , the Sassanids , being Persians , were determined to reconquer lands that the Achaemenid dynasty had once held and now lost . Their nationalistic zeal made them much more aggressive foes of the Romans than the Parthians ever were . For more information , see Byzantine - Sassanid Wars .