2. A son of Attalus I., and brother of Eumenes II., king of Pergamus. In B. C. 171, he was left by Eumenes in charge of the affairs of Pergamus, while the king and Attalus repaired to Greece to assist the Romans in the war against Perseus. With this exception he plays no part in history. (Liv. 42.55; Strab. xiii. p.625; Plb. 40.1.)