The article is devoted to the analysis of the terminology used by the Latin Roman tradition of the 2 nd century CE. The texts associated with coin legends represented the policy of the Roman Empire in the East, in particular in the context of the eastern campaign of Marcus Ulpius Trajan, which ended with the short-term transformation of the territory of Armenia and Northern Mesopotamia into Roman provinces. Not only large texts by Roman authors such as Tacitus, but also small inscriptions on coins were used to characterize the transformation of the territories of Armenia and Northern Mesopotamia into Roman territories. The author offers an original approach to the interpretation of some of the legends found on the issues of Roman coins of the Trajan era and which were associated with attempts to incorporate Armenia and Northern Mesopotamia into the Roman Empire. The formula "IN POTESTATEM P R REDACTAE" finds certain analogies in the texts of the Late Roman Republican era and the time of the Early Empire, which were connected, in particular, with the transformation of Ptolemaic Egypt into a Roman province. In the 2 nd century CE the formula was already used to represent the accession of Armenia and Mesopotamia to Rome.The author, unlike A. Kefelian, who proposed to connect the relevant terminology with legal analogies and property rights in the texts of Roman lawyers, offers his own interpretation. The used terms, in his opinion, were connected with the concept of "deditio in potestatem", which had close ties with the foreign policy aspect of Roman activity, in particular in the East. Coin legends and inscriptions combine two main trends -we can see an appeal both to the victories of the Romans in the East and to the creation of new provinces in the context of the activity of the ruler, in particular through the category of delegated "power of the Roman people" along with "surrender" and "transfer" of certain territories and states under the "power of the people", the symbolic and actual expression of which in the 1 st -2 nd centuries CE was connected with the Emperor. The corresponding study of terminological problems is one of the components of the study of the East image in the Western tradition, in particular in the Classical period.