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, , p. 25. therefore apparently procuring Palmyrene support to his ultimate goal of annexing Charax. It has even been ventured that, when earlier in his campaign Trajan annexed Armenia, he was bound to annex the whole of Mesopotamia lest the Parthians interrupt the flux of trade from the Persian Gulf and/or foment trouble at the Roman frontier on the Danube.Freya Stark, Rome on the Euphrates: The Story of a Frontier.London: I.B. Tauris, 2012, , p. 211. Other historians reject these 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 sourcestrade 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.
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 unitPat Southern Empress Zenobia Palmyra's Rebel Queen London Bloomsbury Publishing 2008  p 25 therefore apparently procuring Palmyrene support to his ultimate goal of annexing Charax It has even been ventured that when earlier in his campaign Trajan annexed Armenia he was bound to annex the whole of Mesopotamia lest the Parthians interrupt the flux of trade from the Persian Gulf and/or foment trouble at the Roman frontier on the DanubeFreya Stark Rome on the Euphrates The Story of a FrontierLondon IB Tauris 2012  p 211 Other historians reject these 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 sourcestrade 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