The form of the word is parallel with Lyciarch, Bithyniarch, etc., but the signification is by no means certain. The title of Asiarch could be held in conjunction with any civil office, and with the high priesthood of a particular city, but the high priest of Asia and the Asiarch were probably not identical; for there was only one high priest of Asia at a time, but there were a number of Asiarchs, as Ac 19:31 shows, even in one city. The honour lasted one year, but re-election was possible. It was held in connexion with the Koinon (Council) of the province, the main duty of which was to regulate the worship of Rome and of the Emperor; and the Asiarchs were probably the deputies to the Council elected by the towns.

A. Souter.