Trajan's Parthian campaign was engaged by Roman emperor Trajan from 113He starded his travel to Antioch on the Orontes in october 113. to 117 against the Parthian Empire in Mesopotamia. The war was initially successful for the Romans, but a series of setbacks, including wide-scale Jewish uprisings in the Eastern Mediterranean and North Africa and Trajan's death in 117, ended in a Roman withdrawal.
In 113, Trajan decided that the moment was ripe for a final resolution of the "eastern question" 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 empire's "grand strategy".Lightfoot (1990), 115: "Trajan succeeded in acquiring territory in these lands with a view to annexation, something which had not seriously been attempted before [...]. Although Hadrian abandoned all of Trajan's conquests [...] the trend was not to be reversed. Further wars of annexation followed under Lucius Verus and Septimius Severus". Sicker (2000), 167–168 In 114, Trajan invaded Armenia; annexed it as a Roman province and killed Parthamasiris, who had been placed on the Armenian throne by his relative, Parthian king Osroes I.Sicker (2000), 167
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 they sailed downriver to the Persian Gulf.
However, revolts erupted that year in the Eastern Mediterranean, North Africa and northern Mesopotamia, while a major Jewish revolt broke out in Roman territory, which severely stretched Roman military resources. Trajan failed to take Hatra. 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 a Parthian prince, Parthamaspates, as a client ruler and withdrew to Syria. Trajan died in 117 before he could renew the war.Sicker (2000), 167–168
Trajan's Parthian campaign is considered in different ways the climax of "two centuries of political posturing and bitter rivalry". He was the first emperor to carry out a successful invasion of Mesopotamia. His grand schemes for Armenia and Mesopotamia were ultimately "cut short by circumstances created by an incorrect understanding of the strategic realities of eastern conquest and an underestimation of what insurgency can do".
Background
In 114, Trajan embarked on his last campaign, provoked by the Parthian Empire's decision to put an unacceptable king on the throne of Armenia, a kingdom over which both empires had shared hegemony since the time of Nero, some 50 years earlier.
Many modern historians consider that Trajan's decision to wage war against Parthia might have had economic motives. After Trajan's annexation of Arabia, he built a new road, Via Traiana Nova, that went from Bostra to Aila on the Red Sea. Charax on the Persian Gulf was thus the sole remaining western terminus of the Indian trade route outside direct Roman control,Christol & Nony, Rome, 171 which was important to lower import prices and to limit the supposed drain of precious metals created by the deficit in Roman trade with the Far East.
That Charax traded with the Roman Empire is certain since actual connections with merchants from Palmyra during the period are well documented in a contemporary Palmyrene epigraph that tells of various Palmyrene citizens honoured for holding office in Charax.Daniel T. Potts, ed., Araby the Blest: Studies in Arabian Archaeology. Copenhagen: Museum Tusculanum Press, 1988, , page 142 Also, Charax's rulers' domains possibly then included the Bahrain islands (where a Palmyrene citizen held office, shortly after Trajan's death, as satrap, but the appointment was made by a Parthian king of CharaxJulian Reade, ed.,The Indian Ocean In Antiquity. London: Routledge, 2013, , page 279), which offered the possibility of extending Roman hegemony into the Persian Gulf itself.Potts, 143 The rationale behind Trajan's campaign would then be to break down a system of Far Eastern trade through small Semitic ("Arab") cities under Parthia's control and to put it under Roman control instead.George Fadlo Hourani, Arab Seafaring in the Indian Ocean in Ancient and Early Medieval Times. Princeton University Press, 1995, , page 15
In his Dacian conquests, Trajan had already resorted to Syrian auxiliary units, whose veterans, along with Syrian traders, had an important role in the subsequent colonization of Dacia. He had recruited Palmyrene units into his army, including a camel unit,Pat Southern, Empress Zenobia: Palmyra's Rebel Queen. London: Bloomsbury Publishing, 2008, , page 25 which apparently procured Palmyrene support to his ultimate goal of annexing Charax. It has even been ventured that in his campaign, when Trajan had annexed Armenia, he was bound to annex the whole of Mesopotamia to prevent the Parthians from interrupting the flux of trade from the Persian Gulf and/or fomenting trouble at the Roman frontier on the Danube.Freya Stark, Rome on the Euphrates: The Story of a Frontier.London: I.B. Tauris, 2012, , page 211
Other historians reject those motives, as the supposed Parthian "control" over the maritime Far Eastern trade route was at best conjectural and based on a selective reading of Chinese sources: trade by land through Parthia seems to have been unhampered by Parthian authorities and left solely to the devices of private enterprise. Commercial activity in second century Mesopotamia seems to have been a general phenomenon, shared by many peoples within and without the Roman Empire, with no sign of a concerted imperial policy towards it. As in the case of the alimenta, scholars like Moses Finley and Paul Veyne have considered the whole idea of a foreign trade "policy" behind Trajan's war anachronistic. According to them, the sole Roman concern with the Far Eastern luxuries trade, besides collecting toll taxes and customs,Paul Erdkamp, The Grain Market in the Roman Empire: A Social, Political and Economic Study. Cambridge University Press, 2005, , page 5 was moral and involved frowning upon the "softness" of luxuries but no economic policy. In the absence of conclusive evidence, trade between Rome and India might have been far more balanced in terms of quantities of precious metals exchanged. One source for the notion of the Roman gold drain, Pliny the Younger's uncle Pliny the Elder, had earlier described the Gangetic Plains as one of the gold sources for the Roman Empire. In his controversial book on the ancient economy, Finley considers Trajan's "badly miscalculated and expensive assault on Parthia" to be an example of the many Roman "commercial wars" that existed only in the books of modern historians.
The alternative view is to see the campaign as triggered by the lure of territorial annexation and prestige, which was the sole motive ascribed by Cassius Dio.
As far as territorial conquest involved collecting taxes,Michael Alexander Speidel: "Bellicosissimus Princeps". In: Annette Nünnerich-Asmus ed., Traian. Ein Kaiser der Superlative am Beginn einer Umbruchzeit? Mainz 2002, pages 23/40. especially of the 25% tax levied on all goods entering the Roman Empire, the tetarte, Trajan's Parthian War could have an "economic" motive. Also, there was the propaganda value of eastern conquests that would emulate, in Roman fashion, those of Alexander the Great.Nathanael John Andrade, "Imitation Greeks": Being Syrian in the Greco-Roman World (175 BCE – 275 CE). Doctoral Thesis, University of Michigan, 2009, page 192. Available at . Retrieved June 11, 2014 The fact that emissaries from the Kushan Empire might have attended to the commemorative ceremonies for the Dacian War may have kindled in some Greco-Roman intellectuals like Plutarch, who wrote that only about 70,000 Roman soldiers were necessary to a conquest of India, and in Trajan's closer associates, speculative dreams about the booty to be obtained by reproducing Macedonian Eastern conquests.Raoul McLaughlin, Rome and the Distant East: Trade Routes to the Ancient Lands of Arabia, India and China. London: Continuum, 2010, , page 130
Also, it is possible that the attachment of Trajan to an expansionist policy was supported by a powerful circle of conservative senators from Hispania committed to a policy of imperial expansion, especially the all-powerful Sura. One can explain the campaign by the fact that for the Romans, their empire was, in principle, unlimited and that Trajan only took advantage of an opportunity to make idea and reality coincide.Dexter Hoyos, ed., A Companion to Roman Imperialism. Leiden: Brill, 2012, , page 262
Finally, there are other modern historians who think that Trajan's original aims were purely military and quite modest: to assure a more defensible eastern frontier for the empire crossing Northern Mesopotamia along the course of the Khabur River to offer cover to a Roman Armenia. That interpretation is backed by the fact that all later Roman wars against Parthia aimed at establishing a Roman presence into Parthia itself.David Kennedy & Derrick Riley, Rome's Desert Frontiers. London: B.T. Datsford Limited, 2004, , pages 31/32
Timeline Plans The campaign was carefully planned in advance: ten legions were concentrated in the Eastern theatre. Since 111, the correspondence of Pliny the Younger witnesses to the fact that provincial authorities in Bithynia had to organise supplies for passing troops, and local city councils and their individual members had to shoulder part of the increased expenses by supplying troops themselves.Fergus Millar, The Roman Near East, 31 B.C. – A.D. 337 (Harvard: University Press, 1993), , p. 103 The intended campaign, therefore, was immensely costly from its very beginning.Michel Christol & D. Nony, Rome et son Empire (Paris: Hachette, 2003), , p. 171
Armenia Trajan marched first on Armenia, deposed the Parthian-appointed king (who was afterwards murdered while he was kept in the custody of Roman troops in an unclear incident that was later described by Fronto as a breach of Roman good faithJohn Rich,Graham Shipley, eds., War and Society in the Roman World. London: Routledge, 1993, , page 235) and annexed it to the Roman Empire as a province. He received in passing the acknowledgement of Roman hegemony by various tribes in the Caucasus and on the Eastern coast of the Black Sea, a process that kept him busy until the end of 114. At the same time, a Roman column under the legate Lusius Quietus, a cavalry generalHermann Bengtson, Römische Geschichte: Republik und Kaiserzeit bis 284 n. Chr. Munich: Beck, 2001, , page 289 who had distinguished himself during the Dacian Wars by commanding a unit from his native Mauretania,Alfred S. Bradford, With Arrow, Sword, and Spear: A History of Warfare in the Ancient World. Westport, CT: Greenwood, 2001, , page 232 crossed the Araxes river from Armenia into Media Atropatene and the land of the Mardians (present-day Ghilan).
It is possible that Quietus's campaign had as a goal to extend the newer more defensible Roman border eastwards towards the Caspian Sea and northwards to the foothills of the Caucasus.S.J. De Laet, review of Lepper, Trajan's Parthian War. L'Antiquité Classique, 18-2, 1949, pages 487–489
Mesopotamia