Formed with the purpose of protecting Athens and its Greek city-states against Persian invasion, the Delian League immediately became a source of conflict between the Greek subject states and Athens. With Sparta refusing to join and Naxos attempting to secede, Athens became increasingly repressive towards the League members. In c. 465 the Athenian general, Kimon, supressed the Thasos rebellion and there was more anger when the League funds were diverted to Athens to pay for its building programme. Skirmishes with the Persians continued, as did revolts against Athenian dominance. Meanwhile, Sparta began to form alliances with disgruntled alliance members. Under Tolmides, an increasingly vulnerable Athens attacked Spartan naval bases, installing Athenian colonies in Naxos and Euboa. The situation escalated in 434 BCE when Perikles’ trade embargo against Sparta’s ally Megera erupted into full blown war between Athens and the Spartan-Greek coalition in 431 BCE.