The Delian League (or Athenian League) was an alliance of Greek city-states led by Athens. The league was formed in 478 BCE to liberate eastern Greek cities from Persian rule. The league was then used as a defence against possible revenge attacks from Persia following the Greek victories at Marathon, Salamis, and Plataea in the early 5th century BCE.
This is a companion discussion topic for the original content at https://www.worldhistory.org/Delian_League/.