(Κτήσιας).
1. Of Cnidus in Caria, and a son of Ctesiochus or Ctesiarchus. (Suid. s. v. Κτήσιας; Eudocia, p. 268; Tzetz. Chil. 1.82.) Cnidus was celebrated from early times as a seat of medical knowledge, and Ctesias, who himself belonged to the family of the Asclepiadae, was a physician by profession. He was a contemporary of Xenophon; and if Herodotus lived till B. C. 425, or, according to some, even till B. C. 408, Ctesias may be called a contemporary of Herodotus. He lived for a number of years in Persia at the court of king Artaxerxes Mnemon, as private physician to the king. (Strab. xiv. p.656.) Diodorus (2.32) states, that Ctesias was made prisoner by the king, and that owing to his great skill in medicine, he was afterwards drawn to the court, and was highly honoured there. This statement, which contains nothing to suggest the time when Ctesias was made prisoner, has been referred by some critics to the war between Artaxerxes and his brother, Cyrus the Younger, B. C. 401. But, in the first place, Ctesias is already mentioned, during that war, as accompanying the king. (Xen. Anab. 1.8.27.) Moreover, if as Diodorus and Tzetzes state, Ctesias remained seventeen years at the court of Persia, and returned to his native country in B. C. 398 (Diod. 14.46; comp. Plut. Art. 21), it follows, that he must have gone to Persia long before the battle of Cunaxa, that is. about B. C. 415. The statement, that Ctesias entered Persia as a prisoner of war, has been doubted; and if we consider the favour with which other Greek physicians, such as Democedes and Hippocrates were treated and how they were sought for at the court of Persia, it is not improbable that Ctesias may have been invited to the court; but the express statement of Diodorus, that he was made a prisoner cannot be upset by such a mere probability. There are two accounts respecting his return to Cnidus. It took place at the time when Conon was in Cyprus. Ctesias himself had simply stated, that he asked Artaxerxes and obtained front him the permission to return. According to the other account. Conon sent a letter to the king, in which he gave him advice as to the means of humbling the Lacedaemonians. Conon requested the bearer to get the letter delivered to the king by some of the Greeks who were staying at his court. When the letter was given for this purpose to Ctesias, the latter inserted a passage in which he made Conon desire the king to send Ctesias to the west, as he would be a very useful person there. (Plut. Art. 21.) The latter account is not recommended by any strong internal probability, and the simple statement of Ctesias himself seems to be more entitled to credit. How long Ctesias survived his return to Cnidus is unknown.