Timaeus and Critias is a Socratic dialogue in two parts. A response to an account of an ideal state told by Socrates, it begins with Timaeus s theoretical exposition of the cosmos and his story describing the creation of the universe, from its very beginning to the coming of man. Timaeus introduces the idea of a creator God and speculates on the structure and composition of the physical world. Critias, the second part of Plato s dialogue, comprises an account of the rise and fall of Atlantis, an ancient, mighty and prosperous empire ruled by the descendents of Poseidon, which ultimately sank into the sea.