Countless sanctuaries characterized the religious landscape of Ancient Greece. Most of them had a local and limited sphere of influence. That is, their geographical connections extended to a single community or, in some cases, only to a part of that community.
However, a group of sanctuaries did develop a much broader degree of support among many communities. In this case we need to distinguish between the spatial and functional dimensions of the various sanctuaries and how the latter interacted with a variety of communities. Indeed, in the transactions, there was considerable overlap in that a dedication might be placed in more than one sanctuary. The contributions of the sanctuaries to the representation not only of their native community, but also to the interregional structure of the Greek world, and to the formation of a Greek identity is readily apparent. Both features developed around the cults of important divinities, communal games, and also through a general practice of preserving official acts in the sanctuaries for the purpose of giving them more visibility. Although the sanctuaries never became a focal point for a continuous peace in the Greek world of states (Koine Eirene) or for any Greek national unity, they did serve as venues for alliance and conciliation. Moreover, the contractual arrangements placed in the sanctuaries evoked a sense of permanence and divine complicity in their enforcement The phenomenon of interregional spheres of influence enjoyed by these sanctuaries will be reviewed in connection with these four sanctuaries: that of Zeus at Olympia, of Apollo at Delphi, of Zeus at Nemea, and of Poseidon at the sanctuary on the Isthmus. Already in the 6th Century BC, all the Greek states had recognized these sanctuaries as the most important in the Greek world. The "political sphere of influence" of these sanctuaries can be identified in the epigraphical sources, and the material itself can be arranged into four categories: official dedications, treaties of alliance and of peace, interregional treaties of varying content, and official honorary inscriptions. A direct comparison of the spheres of influence of Olympia and of Delphi illustrates the differences and similarities that characterize the roles of these sanctuaries. Finally, in section two, we illustrate the sphere of influence of Olympia by looking more closely at the list of Olympic victors as preserved in the literary evidence.