In this period between the Persian Wars and the Peloponnesian War, alliances and leagues sprang up and collapsed, although there was very little prolonged warfare. In 457 Athens, the leader of the Delian League, came into conflict with Corinth and their ally Sparta (leader of the Peloponnesian League) over Megara; two months prior to the Battle of Oenophyta, the Athenians were defeated at the Battle of Tanagra by Sparta, but Sparta had lost so many men that they could not take advantage of their victory.