Delphi reached its height between the 6th and 4th centuries BC, when multitudes of pilgrims came to the sanctuary to consult the oracle.

Delphi was protected by the Amphictyonic League, a federation of 12 tribal states (that unified most of southern Greece), which took control of the sanctuary following the First Sacred War (595–586 BC), making Delphi an autonomous state that enjoyed great prosperity from numerous benefactors, including the kings of Lydia and Egypt, and Hadrian.

The influence of the oracle had a major impact on political and intellectual life, determining – directly or otherwise through the prophecies – such decisions as the establishment of colonies and wars.

The sanctuary survived fire (548 BC) and earthquake (373 BC) and in the 3rd century BC it was conquered by the Aetolians, and then by the Romans in 191 BC. Although the Roman Sulla plundered the sanctuary in 86 BC, other emperors, fascinated by its reputation, kept the rituals at Delphi alive well into the 2nd century AD, when the oracle’s influence began to dwindle. The sanctuary was finally abolished by the Byzantine emperor Theodosius in the late 4th century AD. By the 7th century a new village, Kastri, had appeared over the ancient site. Much of what is known about Delphi today comes from the detailed travel journals of 2nd-century-AD Athenian geographer Pausanius.