The league, throughout the period of its reconstitution in Achaia and its extension outside (that is to say from 280 B.C. to 227 B.C.), was most successful in protecting a number of Greek states from Macedonian interference. But it was never joined by Sparta nor by several other Peloponnesian cities: and about the year 227 B.C. Cleomenes III., one of the two kings of Sparta, wishing at whatever cost to regain for the Spartans their old predominance in the Peloponnesus, found that the Achæan league was an obstacle to his designs: and, having first made an alliance with the Ætolians, who might have put impediments in his way, he became engaged in a war with the Achæans, and, in the course of it, defeated them in three important battles. Aratus and his countrymen in their distress thought it necessary to ask the aid of Antigonus Dôsôn, who was regent in Macedonia as guardian of his nephew the young king: Antigonus readily granted their request, but required them in return to allow him to place a Macedonian garrison in the Acrocorinthus. He entered the Peloponnesus, and, in 222 or 221 B.C. at Sellasia in the north-east corner of the Lacedæmonian territory, the allied armies of Macedonia and Achaia won a great victory and destroyed the power of Cleomenes[256]: but the Achæans found that, by re-admitting the Macedonian power to the Peloponnesus, they had forfeited their independence in regard to foreign policy, and must conform to the wishes of their too powerful ally. The league continued to exist "for another period of seventy-five years, retaining its internal constitution, vastly increased in territorial extent, but, in external affairs, with only a few short intervals, reduced almost to the condition of a dependent ally, first of Macedonia and then of Rome[257]." From the year 146 B.C. Achaia and Macedonia were both included in the dominions of the Roman republic. [256] Polybius II. 45-53 and 64-69. [257] Freeman, _Federal Government_, p. 498. We have now to examine the structure and constitution of the league of cities or cantons[258], which, though it eventually succumbed to Macedonia, had in happier days been distinguished for sixty years of successful assertion of its independence. We will observe first the relation of each component state to the central government, and then proceed to inquire into the nature of the central government itself. [258] Most of the communities in Achaia and some of those in Arcadia were rather cantons than cities: Plutarch (_Aratus_, ch. 9) calls the Achæans μικροπολῖται, citizens of petty towns. Corinth, Argos and Megalopolis were great cities.