The foundation of the Delian League in 478/77 BC is one of the consequences of the victory celebrated by an alliance of several Greek poleis over Persia. As opposed to its antecedents this symmachia was based on a system of fixed contributions, which the members of the League had to pay every year. This new model of financing the fleet of the Delian League together with some other clauses in the treaty might have been the reason for the symmachy’s successful policy in the following years. On the other hand it involved the risk that the hegemonic power could be tempted to abuse its position. The increasing authority of Athens in the Pentecontaetia has already been one of the main topics in the research of Ancient Greek history. In contrast to this the present book is concerned with legal aspects of the Delian League and by interpreting literary and epigraphic sources it tries to reconstruct the form of its charter but also its legal structure. Based on the result of this investigation, the development and transformation of the treaty’s stipulations is illustrated by analysing the cases of League-members who unsuccessfully intended to retire from the alliance.