In contemporary metaphysics, the Eleatic Principle (EP) is a causal criterion for reality. Articulating the EP with precision is notoriously difficult. The criterion purportedly originates in Plato’s Sophist, when the Eleatic Visitor articulates the EP at 247d-e in the famous Battle of the Gods and the Giants. There, the Visitor proposes modifying the ontologies of both the Giants (who are materialists) and the Gods (who are friends of the many forms), using a version of the EP according to which only (...) items which have the capacity to affect or to be affected are real. Recently, it has been argued that while there are some genetic connections between the EP and the views of some of the historical Eleatics (Parmenides and Zeno), the views of Melissus are generally incompatible with the EP. This raises the following question: What, exactly, is Eleatic about the Eleatic Principle? In this paper, I look to the dialectical context in which the Visitor’s appeal to the EP appears, and I propose that there are at once three relevant senses of affecting and being affected in the text: (1) tangible contact (as in the interactions between the bodies of the materialists), (2) Cambridge change (as in the form's being affected by a soul via the act of coming to know), and (3) the notion of a cause that does not itself change (as in a form’s affecting another form, a soul, or any sensible item). I argue that these have clear parallels to the metaphysics of all three main Eleatic philosophers, and that the views of Parmenides, Zeno, and Melissus are therefore compatible with the EP. This has interesting consequences for narratives about the reception of the Eleatics in Plato, the inclusion of an Eleatic Visitor as an interlocutor in the Sophist, and for the metaphysics of subsequent schools (such as the Stoics) who are widely thought to have been influenced by the EP. (shrink)