The war erupted when Sparta detached Delphi from Phocis and rendered it independent, handing it back to the Delphians. The Athenians were however champions of the Phocians. Therefore, in 448 BC, Pericles led the Athenian army against Delphi, in order to reinstate Phocis in its former sovereign rights on the oracle of Delphi. Immediately after the Spartans had left, they recaptured Delphi and handed it back to the Phocians. According to M. Dillon, the military actions of both Sparta and Athens were quick and effective and there is no evidence that they affected pilgrims consulting the oracle.