Delphi

The sanctuary's founding was told as myth: Apollo was said to have killed a serpent living at the site — the she-serpent Delphyne in one account, the serpent Python in another — before making the oracle his own. The Pythia, a woman of the district chosen as priestess, delivered Apollo's oracles from a tripod seat inside the temple's enclosed inner sanctum. Ancient sources describe her falling into a trance believed to come from vapours rising through a fissure in the rock beneath her seat, after which priests turned her utterances into verse. The oracle could not be consulted in winter, when Apollo was said to be absent among the Hyperboreans.

Cities across the Greek world consulted the Pythia before wars and before founding colonies, and her reputation reached to Lydia, Caria and Egypt. Rome's last king, Tarquinius Superbus, is said to have sent two of his sons to consult the oracle after seeing a snake near his palace.

Delphi passed from Phocian control before Athens helped seize it in the First Sacred War (597–585 BC), a conflict that led to the consolidation of the Amphictyonic League, a confederation of city-states with both a military and a religious role protecting the Temple of Apollo. In 586 BC the League inaugurated the Pythian Games, held every four years and ranked second among the four Panhellenic festivals; winners were crowned with a laurel wreath cut by a boy re-enacting Apollo's slaying of the serpent.

The Third Sacred War (356–346 BC) began when the Phocians under Philomelos seized Delphi in 356 BC; the sanctuary's treasuries were plundered during the war to pay the Phocian army, and it ended with Philip II of Macedon defeating the Phocians. A Fourth Sacred War in 339 BC drew Philip back into central Greece and culminated in the Battle of Chaeronea in 338 BC, which established the League of Corinth. Throughout, Greek city-states built treasuries along the Sacred Way to hold a tenth of their war spoils as thanks to the oracle — the Athenian Treasury, restored today, commemorated the victory at Marathon in 490 BC, and the Siphnian Treasury was funded from Siphnos's silver mines until the sea flooded them.

A Gallic invasion under Brennus threatened the sanctuary in 279 BC and was repelled. Delphi came under Roman control in 191 BC and was sacked in 86 BC by the general Sulla during the Mithridatic Wars, who seized the sanctuary's metal votive offerings.

Flavian emperors later funded restoration, and the oracle saw a brief revival under Hadrian, said to have visited twice and granted the city autonomy. Anti-pagan legislation across the late Roman Empire then stripped the sanctuary of its assets, and the emperor Julian's attempt to revive the old cults did not outlast his reign: when he sent his physician Oreibasius to ask the oracle about the fate of paganism, the reply recorded was that Apollo "does not have a home any more, neither an oracular laurel, nor a speaking fountain, because the talking water has dried out." The Pythian Games are attested as late as 424 AD, but the oracle itself was closed by imperial decree under Theodosius I, dated variously to 381, 390 or 395 AD across surviving accounts.

The sanctuary was abandoned in the sixth or seventh century AD, and the fortified village of Kastri grew over its ruins, reusing its stone. The traveller Cyriacus of Ancona, visiting in March 1436 with Pausanias's ancient description as his guide, was the first Westerner to record the visible remains, though some of his identifications were mistaken, including the base of an Argive dedication that he took for the Temple of Apollo. An earthquake in 1500 caused further damage, and in 1766 an English expedition funded by the Society of Dilettanti, including the epigraphist Richard Chandler and the architect Nicholas Revett, surveyed and published the ruins.

Kastri's residents resisted relocation until an earthquake severely damaged the village, after which they accepted a new settlement in exchange for the old site. From 1893 the French Archaeological School cleared landslide soil to expose the sanctuary of Apollo and the temple of Athena Pronoia, also uncovering a fifth-century basilica from Delphi's later life as a bishopric. The precinct has been part of Parnassos National Park since 1938 and is a UNESCO World Heritage Site; finds including the Charioteer of Delphi and the Sphinx of Naxos are held in the Delphi Archaeological Museum.