The project aims to investigate the economic relations of Greek cities between the Classical Age and Hellenism (5^th-1^st centuries B.C.) with the purpose of shedding light on a sector of the ancient Greek economy that is still not sufficiently investigated, while using a new methodological approach. The study will deal with all the external relations activated by the poleis (both towards other communities and towards private foreign citizens), which concern, in whole or in part, economic issues. It will thus be possible to have a clear picture of all the types of economic relations built by the ancient city, both short- and long-range, which reflected different interests and purposes. The former aimed to regulate relations with neighbouring communities for the management of common land and trade resources. Long-range relationships were predominantly the effect of commercial interests. On this basis, a synthesis study will be constructed, investigating the origin and evolution of the economic strategies devised by the ancient city in relation to individual geographical contexts and different historical dynamics. The project is closely related to the line of investigation dedicated to the diplomatic relations between Greek cities (2.1) and to the studies on the ancient economy to which the GEI project is related. A collaboration is planned with the University of Milan Statale.