ARATUS, Greek statesman, was born at Sicyon in 271 B.C., and educated at Argos after the death of his father, at the hands of Abantidas, tyrant of Sicyon. When twenty years old Aratus delivered Sicyon from its tyrant by a bold coup de main. By enrolling it in the Achaean League (q.v.) he secured it against Macedonia, and with funds received from Ptolemy Philadelphus he pacified the returned exiles. Ever anxious to extend the league, in which after 245 he was general almost every second year, Aratus took Corinth by surprise (243), and with mingled threats and persuasion won over other cities, notably Megalopolis (233) and Argos (229), whose tyrants abdicated voluntarily. He fought successfully against the Aetolians (241), and in 228 induced the Macedonian commander to evacuate Attica. But when Cleomenes III. (q.v.) opened hostilities, Aratus sustained several reverses, and was badly defeated near Dyme (226 or 225). Rather than admit Cleomenes as chief of the league, where he might have upset the existing timocracy, Aratus opposed all attempts at mediation. As plenipotentiary in 224 he called in Antigonus Doson of Macedonia, and helped to recover Corinth and Argos and to crush Cleomenes at Sellasia, but at the same time sacrificed the independence of the league. In 220–219 the Aetolians defeated him in Arcadia and harried the Peloponnese unchecked. When Philip V. of Macedon came to expel these marauders, Aratus became the king’s adviser, and averted a treacherous attack on Messene (215); before long, however, he lost favour and in 213 was poisoned. The Sicyonians accorded him hero-worship as a “son of Asclepius.” To Aratus is due the credit of having made the Achaean League an effective instrument against tyrants and foreign enemies. But his military incapacity and his blind hatred of democratic reform went far to undo his work.
Polybius (ii.-viii.) follows the Memoirs which Aratus wrote to justify his statesmanship,—Plutarch (Aratus and Cleomenes) used this same source and the hostile account of Phylarchus; Paus. ii. 10; see Neumeyer, Aratos von Sikyon (Leipzig, 1886). (M. O. B. C.)