Armenian expedition of emperor Constantius II in 338/339 a.d. and military units of Thracian expeditionary army at the Near East: on the late roman military organization in the mid-4th century

The present paper deals with the history of military corps, which Roman emperor Constantius II sent to Great Armenia in 338/339 A.D. for to fight with the Persians. The main evidence on Constantius II’s Persian expedition are preserved in the works of prominent Armenian historians, that are Moses Khorenatsi and Pawstos Buzand. Constantius II held this campaign in order to free Armenia from the Persians and to bring back its state freedom. According to Moses Khorenatsi and Pawstos Buzand, Constantius II sent in Armenia bodyguards, who were representatives of Armenian noble families allied to the Romans, but the Roman regular forces themselves collected in Galatia (the Asia Minor), moved in Mesopotamia and Atropatene (south of modern Azerbaijan and Iranian Azerbaijan). As the author supposes, Roman troops arrived in Armenia and took part in fight with the Persians, strictly due to Roman military help Armenian naχarars could expel the Persians from Armenia. In this connection the author poses a question - which military units arrived at the Roman Near East (in Mesopotamia) from the Asia Minor and how Constantius II’s military campaign in Armenia influenced on the further development of Roman-Persian frontier and its defence system. On the ground of epigraphic data (inscriptions from Mesopotamia and Arabia) author made a conclusion that in 338/339 A.D. Constantius II moved at the Near East military units which previously were parts of Thracian expeditionary army and garrisoned in Thracia, since inscriptions under discussion mention soldiers who bear Thracian names that reveal their Thracian origin.