page_title: Trajan
section_title: Course of the campaign
hierarchical_section_title: Trajan / Roman Emperor / War against Parthia / Course of the campaign
caption_attribution_description: English: This map shows Europe and the Roman Empire at its greatest extent under Trajan in 117 AD.
context_page_description: Trajan was Roman emperor from 98 to 117. Officially declared by the Senate optimus princeps, Trajan is remembered as a successful soldier-emperor who presided over the greatest military expansion in Roman history, leading the empire to attain its maximum territorial extent by the time of his death. He is also known for his philanthropic rule, overseeing extensive public building programs and implementing social welfare policies, which earned him his enduring reputation as the second of the Five Good Emperors who presided over an era of peace and prosperity in the Mediterranean world.
  Trajan was born in Italica, close to modern Seville in present-day Spain, an Italic settlement in the Roman province of Hispania Baetica. Although misleadingly designated by some later writers as a provincial, his Ulpia gens came from Umbria and he was born a Roman citizen. Trajan rose to prominence during the reign of emperor Domitian. Serving as a legatus legionis in Hispania Tarraconensis, in 89 Trajan supported Domitian against a revolt on the Rhine led by Antonius Saturninus. In September 96, Domitian was succeeded by the old and childless Nerva, who proved to be unpopular with the army.
context_section_description: The campaign was carefully planned in advance: ten legions were concentrated in the Eastern theater; since 111, the correspondence of Pliny the Younger witnesses to the fact that provincial authorities in Bithynia had to organize supplies for passing troops, and local city councils and their individual members had to shoulder part of the increased expenses by supplying troops themselves. The intended campaign, therefore, was immensely costly from its very beginning.
  Trajan marched first on Armenia, deposed the Parthian-appointed king, Parthamasiris (who was afterwards murdered while kept in the custody of Roman troops in an unclear incident, later described by Fronto as a breach of Roman good faith), and annexed it to the Roman Empire as a province, receiving 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 – an outstanding cavalry general who had signaled himself during the Dacian Wars by commanding a unit from his native Mauretania – crossed the Araxes river from Armenia into Media Atropatene and the land of the Mardians (present-day Ghilan). It is possible that Quietus' campaign had as its goal the extending of the newer, more defensible Roman border eastwards towards the Caspian Sea and northwards to the foothills of the Caucasus. This newer, more "rational" frontier, depended, however, on an increased, permanent Roman presence east of the Euphrates.
  The chronology of subsequent events is uncertain, but it is generally believed that early in 115 Trajan launched a Mesopotamian campaign, marching down towards the Taurus mountains in order to consolidate territory between the Tigris and Euphrates rivers. He placed permanent garrisons along the way to secure the territory. While Trajan moved from west to east, Lusius Quietus moved with his army from the Caspian Sea towards the west, both armies performing a successful pincer movement, whose apparent result was to establish a Roman presence into the Parthian Empire proper, with Trajan taking the northern Mesopotamian cities of Nisibis and Batnae and organizing a province of Mesopotamia, including the Kingdom of Osrhoene – where King Abgaros VII submitted to Trajan publicly – as a Roman protectorate. This process seems to have been completed at the beginning of 116, when coins were issued announcing that Armenia and Mesopotamia had been put under the authority of the Roman people. The area between the Khabur River and the mountains around Singara seems to have been considered as the new frontier, and as such received a road surrounded by fortresses.
  After wintering in Antioch during 115/116  – and, according to literary sources, barely escaping from a violent earthquake that claimed the life of one of the consuls, M. Pedo Virgilianus – Trajan again took to the field in 116, with a view to the conquest of the whole of Mesopotamia, an overambitious goal that eventually backfired on the results of his entire campaign. According to some modern historians, the aim of the campaign of 116 was to achieve a "preemptive demonstration" aiming not toward the conquest of Parthia, but for tighter Roman control over the Eastern trade route. However, the overall scarcity of manpower for the Roman military establishment meant that the campaign was doomed from the start. It is noteworthy that no new legions were raised by Trajan before the Parthian campaign, maybe because the sources of new citizen recruits were already over-exploited.
  As far as the sources allow a description of this campaign, it seems that one Roman division crossed the Tigris into Adiabene, sweeping south and capturing Adenystrae; a second followed the river south, capturing Babylon; Trajan himself sailed down the Euphrates from Dura-Europos – where a triumphal arch was erected in his honour – through Ozogardana, where he erected a "tribunal" still to be seen at the time of Julian the Apostate's campaigns in the same area. Having 
caption: The Roman Empire under Trajan, 117 AD
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