(Θρασύβουλος), a friend and contemporary of Galen, in the latter half of the second century after Christ. Galen addressed two of his works to him, viz. De Optima Secta (vol. i. p. 106) and Utrum Medicinae sit an Gymnasticcs Hygieine (vol. v. p. 806); but it does not seem certain that he was a physician.