Timaeus is one of Plato's dialogues, mostly in the form of a long monologue given by the title character Timaeus of Locri, written c. 360 BC. The work puts forward speculation on the nature of the physical world and human beings and is followed by the dialogue Critias. Participants in the dialogue include Socrates, Timaeus, Hermocrates, and Critias. Some scholars believe that it is not the Critias of the Thirty Tyrants who is appearing in this dialogue, but his grandfather, who is also named Critias. It has been suggested that Timaeus influenced a book about Pythagoras, written by Philolaus. Critias, one of Plato's late dialogues, recounts the story of the mighty island kingdom Atlantis and its attempt to conquer Athens, which failed due to the ordered society of the Athenians. Critias is the second of a projected trilogy of dialogues, preceded by Timaeus and followed by Hermocrates.The latter was possibly never written and Critias was left incomplete. Because of their resemblance (e.g. in terms of persons appearing), modern classicists occasionally combine both Timaeus and Critias as Timaeus-Critias.