Decapolis [Gr.,=ten cities], confederacy of 10 ancient cities, all E of the Jordan, except Scythopolis. The others were (according to Pliny) Dion, Pella, Gadara, Hippos, Gerasa, Philadelphia, Damascus, Raphana, and Kanatha. The league was constituted after Pompey's campaign (65 B.C.-62 B.C.) as a protection against the Jews and the Arabian tribes and as a customs union. The Roman governor of Syria exercised general supervision of its affairs, and the cities belonging to the league were liable to Roman military service and taxation.