(Εὔπομπος), of Sicyon, one of the most distinguished Greek painters, was the contemporary of Zeuxis, Parrhasius, and Timanthes, and the instructor of Pamphilus, the master of Apelles. He was held in such esteem by his contemporaries, that a new division was made of the schools of art, and he was placed at the head of one of them. Formerly only two schools had been recognized, the Greek Proper or Helladic, and the Asiatic; but the fame of Eupompus led to the creation of a new school, the Sicyonian, as a branch of the Helladic, and the division then adopted was the Ionian, the Sicyonian, and the Attic, the last of which had, no doubt, Apollodorus for its head. Another instance of the influence of Eupompus is his celebrated answer to Lysippus, who, at the beginning of his career, asked the great painter whom he should take for his model; and Eupompus answered that he ought to imitate nature herself, and no single artist. The only work of Eupompus which is mentioned is a victor in the games carrying a palm. (Plin. Nat. 34.8. s. 19.6, 35.9, 10. s. 36. §§ 3, 7.)
[P.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890