Kommerkiarios

The kommerkiarios (Greek: κομμερκιάριος) was a fiscal official of the Byzantine Empire charged with the collection of the imperial sales tax or kommerkion.

The kommerkiarios was perhaps the successor of the comes commerciorum, which was a late Roman controller of trade on the frontier. According to the late 4th-century Notitia Dignitatum, there were three comites commerciorum under the control of the comes sacrarum largitionum: one for Oriens and Egypt, one for Illyricum, and one for Moesia, Scythia Minor and Pontus (i.e. the Danube frontier and the Black Sea).

The term kommerkiarios first appears in fragmentary inscriptions of a law issued by Emperor Anastasios I (r. 491–518). The kommerkiarioi were stationed in many areas of the frontier, as indicated by their seals, which appear to substantiate the statement made by the 6th-century historian Procopius about Emperor Justinian I (r. 527–565) installing customs stations "at each strait" and sending two archontes to every location in order to collect tolls.Gabriel Millet, a French Byzantinist, considered the early kommerkiarioi as merchants of the Byzantine emperor, but his views are deemed questionable.

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