What was the alliance of greek city states under the leadership of Athens called?

The alliance of Greek city-states under the leadership of Athens was called the Delian League. Established in 478 BCE, it was formed primarily to continue the fight against Persia after the Persian Wars. Member states contributed ships and money, with the league's treasury initially located on the island of Delos. Over time, Athens became increasingly dominant, leading to tensions with other city-states and contributing to the outbreak of the Peloponnesian War.