During the Second Sacred War Pericles led the Athenian army against Delphi and reinstated Phocis in its sovereign rights on the oracle. In 447 BC Pericles engaged in his most admired excursion, the expulsion of barbarians from the Thracian peninsula of Gallipoli, to establish Athenian colonists in the region. At this time, however, Athens was seriously challenged by a number of revolts among its subjects. In 447 BC the oligarchs of Thebes conspired against the democratic faction. The Athenians demanded their immediate surrender, but after the Battle of Coronea, Pericles was forced to concede the loss of Boeotia to recover the prisoners taken in that battle. With Boeotia in hostile hands, Phocis and Locris became untenable and quickly fell under the control of hostile oligarchs.