The first group under this name was formed for mutual protection against pirates, though not much else is known.  
The first group under this name was formed for mutual protection against pirates, though not much else is known.  This group's second and more famous incarnation was founded in order to free Sicyon from tyranny and fell under the leadership of Aratus.  It fell into conflict with Cleomenes III of Sparta and sought Macedonian aid against the Aetolian League in 227 BCE.  Later, the Romans deported this organization's leaders, including Polybius, and defeated them at the Battle of Corinth.  FTP, identify this group of Greek city-states whose goal was Greek liberty.
The first group under this name was formed for mutual protection against pirates, though not much else is known.  
Achaean League