A Greek historian, contemporary with Thucydides, about 400 B. C. He continued the work of the great historian, and brought it down, according to Plutarch, to the time of Conon. The well known words of Dionysius, "He wrote what Thucydides left unwritten," evidently show that Cratippus not only continued the history of Thucydides, but also supplied whatever omissions he thought he found in it. II. A celebrated Peripatetic philosopher. He was born about 75 B. C, at Mytilene, on the island of Lesbos, where he established a school of philosophy; but afterward having repaired to Athens, he became the instructor of Brutus and of M. Cicero, the son of the great Roman orator. Cicero himself pronounces high encomiums upon him in the De Officiis, declaring him the ablest of the Peripatetics whom he had ever known, and equal at least to the best of the school. Though highly esteemed by the ancients, he probably never produced any important philosophical work. Cicero tells us that he believed in inspiration and in dreams, but rejected all other kinds of divination.

He is supposed to have been the author of the work on dreams cited by Tertullian in his work De Anima.