The Achaean League was a confederation of city-states in ancient Greece, primarily located in the region of Achaea. Established in the 3rd century BCE, it aimed to promote mutual defense and economic cooperation among its member cities. The league played a significant role in the political landscape of Greece, especially during the Hellenistic period. The Achaean League was known for its democratic principles, allowing member states to participate in decision-making. It reached its peak in the 2nd century BCE, when it successfully resisted external threats, including the Macedonian Empire. However, the league eventually fell under Roman control after the Battle of Corinth in 146 BCE.