Delphi is both an archaeological site and a modern town in Greece on the south-western spur of Mount Parnassus in the valley of Phocis. In myths dating to the classical period of Ancient Greece (510-323 BC), the site of Delphi was believed to be determined by Zeus when he sought to find the centre of his “Grandmother Earth” (Ge, Gaea, or Gaia). He sent two eagles flying from the eastern and western extremities, and the path of the eagles crossed over Delphi where the omphalos, or navel of Gaia was found.
Earlier myths include traditions that Pythia, or the Delphic oracle, already was the site of an important oracle in the pre-classical Greek world (as early as 1400 BC) and, rededicated, served as the major site during classical times for the worship of the god Apollo after he slew Python, “a dragon” who lived there and protected the navel of the Earth. “Python” (derived from the verb pythein, “to rot”) is claimed by some to be the original name of the site in recognition of Python which Apollo defeated. The Homeric Hymn to Delphic Apollo recalled that the ancient name of this site had been Krisa. Others relate that it was named Pytho and that Pythia, the priestess serving as the oracle, was chosen from their ranks by a group of priestesses who officiated at the temple.
The Pythia, commonly known as the Oracle of Delphi, was the name of any priestess throughout the history of Temple of Apollo at Delphi, located on the slopes of Mount Parnassus, beneath the Castalian Spring (the new priestess was selected after the death of the current priestess). The Pythia was widely credited for her prophecies inspired by Apollo. The Delphic oracle was established in the 8th century BC, although it may have been present in some form in Late Mycenaean times, from 1400 BC and was abandoned, and there is evidence that Apollo took over the shrine from an earlier dedication to Gaia. The last recorded response was given about 395 A.D. to Emperor Theodosius I, after he had ordered pagan temples to cease operation. During this period the Delphic Oracle was the most prestigious and authoritative oracle among the Greeks. The oracle is one of the best-documented religious institutions of the classical Greeks. Authors who mention the oracle include Aeschylus, Aristotle, Clement of Alexandria, Diodorus, Diogenes, Euripides, Herodotus, Julian, Justin, Livy, Lucan, Ovid, Pausanias, Pindar, Plato, Plutarch, Sophocles, Strabo, Thucydides, and Xenophon.
The name “Pythia” derived from Pytho, which in myth was the original name of Delphi. The Greeks derived this place name from the verb, pythein (πύθειν, “to rot”), which refers to the decomposition of the body of the monstrous Python after she was slain by Apollo. The usual theory has been that the Pythia delivered oracles in a frenzied state induced by vapors rising from a chasm in the rock, and that she spoke gibberish which priests interpreted as the enigmatic prophecies preserved in Greek literature.
Recent geological investigations have shown that gas emissions from a geologic chasm in the earth could have inspired the Delphic Oracle to “connect with the divine.” Some researchers suggest the possibility that ethylenegas caused the Pythia’s state of inspiration. However, Lehoux argues that ethylene is “impossible” and benzene is “crucially underdetermined.” Others argue instead that methane might have been the gas emitted from the chasm, or CO2 and H2S, arguing that the chasm itself might have been a seismic ground rupture. The idea that the Pythia spoke gibberish which was interpreted by the priests and turned into poetic iambic pentameter has been challenged by scholars who argue that the ancient sources uniformly represent the Pythia speaking intelligibly, and giving prophecies in her own voice.