_ Source: _Volume 10, Issue 1, pp 65 - 94 In his highly influential 1928 article ‘The _Parmenides_ of Plato and the Origin of the Neoplatonic “One”,’ E.R. Dodds argued, _inter alia_, that among the so-called Neoplatonists Plotinus was the first to interpret Plato’s _Parmenides_ in terms of the distinctive three ‘hypostases’, One, Intellect, and Soul. Dodds argued that this interpretation was embraced and extensively developed by Proclus, among others. In this paper, I argue that although Plotinus took _Parmenides_ to (...) contain a sort of outline of the true metaphysical principles, he understood the One of the first hypothesis of the second part of the dialogue in a way importantly different from the way that Proclus understood it. The characterization of this One, especially its identity with the Idea of the Good of _Republic_, has significant ramification for Plotinus’ philosophy that set it apart from Proclus’ philosophy in ways hitherto infrequently noted. The widely accepted reasons for rejecting Proclus’ interpretation do not apply to the interpretation of Plotinus. The two different interpretations help explain why Proclus’ notorious proliferation of entities in the intelligible realm is not found in Plotinus. (shrink)