(Ι᾿ούλιος Πολυδεύκης ), a celebrated Greek sophist and grammarian, who flourished near the close of the 2d century, was a native of Anacratis, in Egypt, and, after preparatory training under his father, studied at Athens under the rhetorician Adrian. He finally opened a school himself, and was subsequently appointed by the emperor Commodus to the chair of rhetoric. Several of his contemporaries thereafter attacked him, and in many ways aimed to detract from his scholarly repute. He was the author of several works, of which Suidas has preserved the titles. None of them are of interest to us except the Ο᾿νομαστικὸν ἐν Βιβλίοις, which has come down to us, and is valuable because it treats in the first part of the gods and their worship. See Fabricius, Bibl. Graeca, 6:141; Grafenhahn, Gesch. der class. Philology, 3, 166 sq.