A hypothesis first proposed in the nineteenth century has since the middle of the twentieth century been approaching mythical status. It is the hypothesis that in the course of Plato’s philosophical ‘development’, he passed through a ‘Socratic period’ in which he was principally devoted to representing the philosophy of the historical Socrates rather than his own. This Socratic philosophy is found in the so-called early dialogues and is sometimes called ‘Socratic intellectualism’. According to the myth, Plato only developed and wrote down his own philosophical position in the middle and late dialogues. In this paper, I challenge the myth, arguing that there is no external evidence to support the initial hypothesis and significant evidence for rejecting it. In fact, Plato was probably in some sense a proponent of Pythagoreanism and a ‘two-world metaphysics’ well before he wrote anything. The claim that, external evidence notwithstanding, the early dialogues actually contain a philosophical position substantially different from that of later dialogues is also unfounded. Although Plato’s thought continually developed within the context of ongoing Academic discussions, nowhere in any of the dialogues is Plato’s ‘otherworldy’ revisionist philosophy absent.