Critias (//; Greek: Κριτίας, Kritias; c. 460 – 403 BC) was an ancient Athenian political figure and author. Born in Athens, Critias was the son of Callaeschrus and a first cousin of Plato's mother Perictione. He became a leading and violent member of the Thirty Tyrants. He also was an associate of Socrates, a fact that did not endear Socrates to the Athenian public.
Critias was noted in his day for his tragedies, elegies, and prose works. Sextus Empiricus attributed the Sisyphus fragment to Critias; others, however, attribute it to Euripides. His only known play is Peirithous. In addition, eight shorter quotations from unidentified plays have come down to us.
Critias gave an account of his ancestry which was later recorded in Plato's Timaeus. Critias's great-grandfather, Dropidas, was an intimate friend of Solon. Dropidas's son, also named Critias, was the grandfather and namesake of the author Critias.
Critias was once a student of Socrates. The two had a strained relationship. However, it is said that Critias was the one who saved Socrates from persecution during the terror of the Thirty Tyrants. However, Critias was very greedy, something that Socrates did not approve of.
Critias was killed in a battle near Piraeus, the port of Athens, between a band of pro-democracy Athenian exiles led by Thrasybulus and members and supporters of the Thirty, aided by the Spartan garrison. In the battle, the exiles put the oligarchic forces to flight, ending the rule of the Thirty.
According to the Pyrrhonist philosopher, Sextus Empiricus, Critias denied that the gods existed. Critias also asserted that "a shrewd and clever-minded man invented for mortals a fear of the gods, so that there might be a deterrent for the wicked..." The text from which this excerpt originates is known both as the "Critias fragment" and the "Sisyphus fragment." Its origins are disputed. Most historians attribute the quotation to the character of Sisyphus in a play by Euripides, but Sextus Empiricus attributed it to Critias.
In the Charmides, Plato implies that Critias' philosophy was that temperance was the art of "doing our own business." Socrates spends the rest of the dialogue challenging this definition as vague and meaningless.
The Critias character in Plato's dialogues Timaeus and Critias is often identified as the son of Callaeschrus – but not by Plato. Given the old age of the Critias in these two dialogues, he may be the grandfather of the son of Callaeschrus.
Then listen, Socrates, to a strange tale which is, however, certainly true, as Solon, who was the wisest of the seven sages, declared. He was a relative and a great friend of my great-grandfather, Dropidas, as he himself says in several of his poems; and Dropidas told Critias, my grandfather, who remembered and told us: That there were of old great and marvelous actions of the Athenians, which have passed into oblivion through time and the destruction of the human race, and one in particular, which was the greatest of them all [...]