Achaean League

Union in 280 BC of most of the cities of the northern Peloponnese, which managed to defeat Sparta, but was itself defeated by the Romans in 146 BC.

During the 4th century BC the early league formed by 12 cities of Achaea fought in the wars between Thebes and Sparta, as well as against Philip II and Antipater of Macedon. It was dissolved by Antigonus II Gonatus; but by 280 BC four cities had reunited, and before long all ten of those that survived had done the same. Thanks to the expansive policy of the Greek soldier Aratus of Sicyon, the league included in 228 BC Arcadia, Argolis, Corinth, and Aegina; but between that date and 220 BC it lost much territory as a result of wars with Cleomenes III of Sparta and with the Aetolians, becoming subject to Macedonia. Some ground was recovered under the general Philopoemen, and in return for Achaean neutrality during the Macedonian wars (215-197 BC) Rome restored all the League's former possessions and made it virtually supreme in Peloponnesus. In 150 BC however, the League attacked Sparta in defiance of orders from Rome. Its army was defeated by the Roman general Mummius near Corinth 146 BC, and Greece was formed into the Roman province of Achaea.