Achaean League. The inhabitants of Achaia were a very inconsiderable member of the Hellenic family until about 251 B. C. They formed 12 separate self-governing communities, united together only by the religious bond of a common temple, common festivals, and common ancestry. In the repulse of the Persian invaders, in the Peloponnesian war, and in the resistance to Macedonian conquest, they took little part; and it was not until Athens, Thebes, and Lacedaemon had been subdued or humbled by Macedonian supremacy, that the insignificant Achaeans became illustrious. When the Macedonian monarchy was reeling beneath the invasion of the Gauls, four Achaean towns formed a league for mutual protection in 281. Soon afterward Aegium ejected its garrison, and some others forced their tyrants, who governed in the Macedonian interest, to lay down their authority. In 251 Aratus, the Sicyonian, brought round his native town to the Achaean league, and got himself elected head of the confederacy. Corinth was freed from its garrison in 243 by the aid of the league, and was admitted a member. Megara, Epidaurus, Troezen, and the Arcadian cities joined soon after. In 208 Philipœmen, of Megalopolis, succeeded Aratus as general of the league.

At this time, and especially after the total defeat of the Macedonian monarch at Cynoscephalae, it was the only powerful state left in Greece, and the only possible bulwark against Roman power. When Sparta joined the league in 191 it included almost all the cities of the Peloponnesus, together with Athens, and several cities of northern Greece. For 50 years the Achaean confederation maintained the cause of Hellenic independence, and delayed the day of submission to Rome. (See Greece.) At last the Roman senate succeeded in getting grounds of quarrel with the league, and sent Mummius over to complete the subjugation of Hellas. This was done in 146 by the defeat of Diaeus, the general of the confederates, before the walls of Corinth. All Greece was then made into a Roman province, under the name of Achaia. - The Achaean league is the best example of the federative system bequeathed to the world by the Greeks. Each state or city, whether large or small, had but one vote, and retained its power of internal legislation, as well as its separate coins, weights, and measures, though the federal government had also its coins, weights, and measures, which were uniform.

The right of intermarriage without loss of the children's citizenship, and the right of holding property and of importing and exporting on favorable terms, existed between the several cities of the federation, until taken away by the Romans, by way of punishment for resistance to their policy. The general assembly was held twice a year, but extraordinary assemblies were sometimes called. At the spring meeting the strategus or commander-in-chief, the hippar-chus or master of the horse, and ten other functionaries called demiurgi, were elected. Although every citizen who could afford it might attend these assemblies, all the citizens of any one city could only throw one vote, a fact which made the larger cities, such as Corinth, discontented. Such a confederation in the age of Philip would probably have prevented the Macedonian conquest.