 The opening conversation (17a1–27d4) introduces the characters—Socrates, Timaeus, Critias and Hermocrates—and suggests that the latter three would contribute to a reply to Socrates’ speech allegedly given on the previous day, which presented an ideal political arrangement strongly reminiscent of the  Republic.[3]  This reply would start with an account of the creation of the universe down to the creation of human beings and, in a second step, show an ideal society in motion. Critias is meant to provide the second step with his account of a war between ancient Athens and Atlantis, the beginning of which we find in Plato’s Critias, while Timaeus is meant to deal with the first step in our dialogue. Timaeus begins the discourse (27d5–92c9) with a prologue (27d5–29d6) in which he sets out the metaphysical principles on which his account is based, introduces the figure of the Craftsman and his eternal model, and provides a brief comment on the status of the account he is about to provide. This prologue is followed by the discourse proper, which is uninterrupted to the end of the dialogue (29d7–92c9). The discourse unfolds in three main stages: the first sets out the achievements of Intellect (29d7–47e2), the second gives an account of the effects of Necessity (47d3–69a5), and the third shows how Intellect and Necessity cooperate in the production of the psychophysical constitution of human beings (69a6–92c9).