Delphi
In 356 BC the Phocians under Philomelos captured and sacked Delphi, leading to the Third Sacred War (356–346 BC), which ended with the defeat of the former and the rise of Macedon under the reign of Philip II. This led to the Fourth Sacred War (339 BC), which culminated in the Battle of Chaeronea (338 BC) and the establishment of Macedonian rule over Greece.
In Delphi, Macedonian rule was superseded by the Aetolians in 279 BC, when a Gallic invasion was repelled, and by the Romans in 191 BC. The site was sacked by Lucius Cornelius Sulla in 86 BC, during the Mithridatic Wars, and by Nero in 66 AD. Although subsequent Roman emperors of the Flavian dynasty contributed towards to the restoration of the site, it gradually lost importance. In the course of the 3rd century mystery cults became more popular than the traditional Greek pantheon. Christianity, which started as yet one more mystery cult, soon gained ground, and this eventually resulted in the persecution of pagans in the late Roman Empire. The anti-pagan legislation of the Flavian dynasty deprived ancient sanctuaries of their assets. The emperor Julian attempted to reverse this religious climate, yet his "pagan revival" was particularly short-lived. When the doctor Oreibasius visited the oracle of Delphi, in order to question the fate of paganism,he received a pessimistic answer:
Third Sacred War
In early 346 BC, Philip let it be known that he intended to march south with the Thessalians, though not where or why. The Phocians thus made plans to defend Thermopylae, and requested assistance from the Spartans and the Athenians, probably around 14 February. The Spartans dispatched Archidamus III with 1,000 hoplites, and the Athenians ordered everyone eligible for military service under the age of 40 to be sent to the Phocians' aid. However, between the Phocians' appeal and the end of the month, all plans were upset by the return of Phalaikos to power in Phocis; the Athenians and the Spartans were subsequently told that they would not be permitted to defend Thermopylae. It is not clear from the ancient sources why Phalaikos was returned to power, nor why he adopted this dramatic change of policy. Cawkwell suggests, based on remarks of Aeschines, that the Phocian army restored Phalaikos because they had not been properly paid, and further that Phalaikos, realizing that the army could not be paid and that the Phocians could no longer hope to win the war, decided to try to negotiate a peace settlement with Philip.