_Panætius_ was a native of Rhodes; his exact age is not known, but he was a contemporary of Scipio Æmilianus, who died B.C. 129. He went to Athens at an early age, where he is said to have been a pupil of Diogenes of Babylon and Antipater of Tarsus, and also of Polemo Periegetes. He became associated with P. Scipio Æmilianus, who valued him highly. The latter part of his life he spent at Athens, where he had succeeded Antipater as head of the Stoic school. He was the author of a treatise on “What is Becoming,” which Cicero professes to have imitated, though carried rather further, in his De Officiis. He softened down the harsher features of the Stoic doctrines, approximating them in some degree to the opinions of Xenocrates, Plato, and Aristotle, and made them attractive by the elegance of his style; indeed, he modified the principles of the school so much, that some writers called him a Platonist. In natural philosophy he abandoned the Stoic doctrine of the conflagration of the world; endeavoured to simplify the division of the faculties of the soul; and doubted the reality of the science of divination. In ethics he followed the method of Aristotle; and, in direct opposition to the earlier Stoics, vindicated the claim of certain pleasurable sensations to be regarded as in accordance with nature. _Polemo_ was a pupil of Xenocrates, and succeeded him as the head of his school. There is a story that he had been a very dissolute young man, and that one day, at the head of a band of revellers, he burst into the school of Xenocrates, when his attention was so arrested by the discourse of the philosopher, which happened to be on the subject of temperance, that he tore off his festive garland, remained till the end of the lecture, and devoted himself to philosophy all the rest of his life. He does not appear to have varied at all from the doctrines of his master. He died B.C. 273. _Archytas_ was a native of Tarentum: his age is not quite certain, but he is believed to have been a contemporary of Plato, and he is even said to have saved his life by his interest with the tyrant Dionysius. He was a great general and statesman, as well as a philosopher. In philosophy he was a Pythagorean; and, like most of that school, a great mathematician; and applied his favourite science not only to music, but also to metaphysics. Aristotle is believed to have borrowed from him his System of Categories.