Thucydides provides just one example of the use of force to extend membership of the League, but since his account seems to be selective, there were presumably more; certainly, Plutarch provides details of one such instance. Karystos, which had collaborated with the Persians during the second Persian invasion, was attacked by the League at some point in the 470s BCE, and eventually agreed to become a member. Plutarch mentions the fate of Phaselis, which Cimon compelled to join the league during his Eurymedon campaign.