The name of the fortress Κουμαρκίανα is one of the only here witnessed place-names in Prokopius’ Buildings. This fact, certainly, leads to a more difficult interpretation of linguistic origin of the toponym and its identification, as well. Consequently, the main part of the article examines the probable etymology of this unique name. Contrary to the prevailing view that it belongs to a large and productive group of Latin place-names with personal Latin name and specific suffixes -iana / janon, our thesis is different. Although unusual for this type of names, we assume that its basis is an appellative, Latin noun commercium which in the Greek language from a later period was taken over as κομ(μ)έρκιον and κουμμέρκιον with the meaning of „customs station, customs“. Further, in close relation with the meaning, consideration of localization of Prokopius’ fortress is followed.
