As the legend goes, Coretas the goat herder and his flock wandered across a high ridge overlooking a valley of pine and laurel. He stopped by a cluster of rocks while his goats drank from a spring.
Something shifted in their bleating. Leaping around the rocks, spear at the ready, he discovered his charges standing over a rift in the rocks. His goats were staring into the fissure, swaying strangely.
The shepherd approached. A sweet smell was on the air; his thoughts began drifting. Strange visions of things long past and yet to be. He fell to his knees in prayer to Gaia, the earth mother: the visions must be rising from her sacred place beneath the earth.
Coretas shared the story of his encounter with the Goddess on his return home. Those that visited the chasm found their own visions, and spoke strangely while under her influence. Occasionally the Goddess would drive men, in spontaneous frenzy, to leap to their deaths on the rocks.
For safety, a divine intercessor was appointed: a ritually purified priestess called Pythia. A cult grew up around her. This legendary story becomes concrete with a shrine constructed around 1400 BC, rediscovered by French archeologists in 1892 AD. At the heart of the shrine, in a chamber only she could enter – called the adyton – Pythia perched on a tripod over the fissures to draw in the divine influence and issue her riddling prophecies.

Right: Modern painting of Pythia. Collier, John, “Priestess of Delphi”, 1891, Wikimedia.
For the next two thousand years, pilgrims journeyed to Delphi on sacred days to offer gifts and sacrifices in exchange for the oracle’s divine thoughts. At first, they consulted her only on personal matters: resolution of feuds, religious decisions, marriages, travel plans and business ventures. In time, her reach would grow far beyond anything she could imagine.
To build the significance of the site and perhaps to wrest control from the all-female priestesses, the worship of Gaia was stripped away and it was reconsecrated around 800 BC to Apollo, son of Zeus. As a concession, Pythia would retain her role, but her divinely-inspired pronouncements would ever after be interpreted by the prophetes: Apollo’s male priests.
Pythia was always chosen from among the peasant women of Delphi. No special education or qualification was required . After a young virgin consecrated as Pythia was seduced, or raped, – risking the wrath of Apollo for despoiling his sacred vessel – women had to be over 50 years old. They did not have to be virgins, but they did have to keep chaste during their tenure as Pythia.
Just how much influence could the predictions of an uneducated elderly peasant woman from rural Delphi have on the wider world? It was a deadly misunderstanding that would cement her reputation and lead even kings and emperors to seek her advice, advice that would transform the ancient world.
Croesus was worried. The undisputed ruler of Lydia, covering most of Asia Minor, was an enviable position. His reign had been marked by stability and great prosperity, as was his fathers before him. In his youth, he had led his army on a series of successful campaigns securing him all of what is now western Turkey. His empire’s wealth was legendary, built on gold mines, important trading ports, and its position as a gateway between Central Asia and the Mediterranean.

Nearly fifty years old, he was no longer the rampager of his youth. He had grown satisfied with his status and become more inclined to spectacle than warfare. In their sumptuous dress and jewelry, his courtiers at Sardis strove to outdo each other, but Croesus outshone them all. Under Croesus, the enterprising Lydians invented the use of coins as currency. In time, Lydia’s pure gold and silver coins, each stamped with the symbols of their kingdom and hinting at its great wealth, travelled far beyond their borders. Such wealth can attract trouble – and trouble was brewing to the east.
Where Croesus was inclined to rest on his laurels, Cyrus was a hungry young whirlwind. The ruler of the Persians, a minor people in the vast Median empire, wanted much more. For Cyrus’ ambitions to be realised, the unpopular Medes would have to go. This novice king would first need to convince his men to risk everything in rebellion against their emperor:
He pointed out to them a barren, thorny spot, and ordered them to clear and cultivate it. When with great labour and fatigue they had completed this task, the next day he ordered them to bathe and clean themselves, and come to a sumptuous feast which he had prepared for them.
After they had spent the day in such luxury, he asked them which of the two days they preferred. They replied that the present day was as much preferable to the former, as happiness is to misery. “It is in your power then,” said Cyrus, “to obtain happiness. Free yourselves from your slavery under the Medes.”
The Persians, struck by the greatness of this proposal, revolted and appointed Cyrus to be their king.
Polyaenus, Stratgems of War. Book 7, 6.7. Source: Attalus
Having convinced his people, Cyrus next talked the Median general into defecting, leaving their army in disarray. His men now easily overran the capital and ended one-hundred and fifty years of Median rule. Cyrus now found himself ruler of a huge region from the Indus river in the East, through modern-day Pakistan, Afghanistan, Iran and eastern Turkey. And just over his new border in the West, the fabulously wealthy Lydians.
News of the Medes’ defeat shook Croesus. His upstart Persian neighbour, near seven-fold his size, had toppled his Median ally and brother-in-law. Thirty-five years earlier, Croesus’ father had fought the Medes to a stalemate when, in the midst of a battle at the Halys river, the Gods had blotted out the sun in the sky. Both sides at once sought peace, agreed to set their border at the Halys and the Median emperor married Croesus’ sister. Such omens were not to be ignored.
Now Croesus had to weigh crossing the gods and the Halys to face this unknown foe. Could Cyrus’ nascent empire fall as easily as the Medes’ had? A hasty offensive might seize vast territory, avenge his brother-in-law, and restore security to his kingdom. It was a gamble, but the Lydians were consummate gamblers: they invented dice. First he wanted to make sure the odds were in his favour, and who better to ask than the Gods themselves.

The glamorous king was no fool. If Croesus could be sure of an oracle’s prophetic power, he could wield this to defeat his Persian foes. With seven messengers and one question, he tested the best-known oracles around the ancient world. Each messenger was dispatched from Sardis with strict instructions to present their oracle the question at the same time on the same day. The question was simple: what is our king doing right now?
Exactly one hundred days after his messengers had departed, Croesus boiled up some tortoise and lamb in a bronze cauldron. As each messenger trickled back into Sardis, Croesus grew more frustrated. All had failed him. Finally, Pythia’s message arrived from distant Delphi. Croesus threw up his arms in joy. For on her message was written:
I count the grains of sand on the beach and measure the sea; I understand the speech of the dumb and hear the voiceless. The smell has come to my sense of a hard shelled tortoise boiling and bubbling with a lamb’s flesh in a bronze pot: the cauldron underneath it is of bronze, and bronze is the lid.
Herodotus, Histories I, 47. Source: LacusCurtius.
Croesus was effusive, heaping worship on Apollo and lavish gifts on Delphi. He had a stone palace built there just to house all the treasures he sent. This gesture set a new standard and in time many leaders would vie to outdo it. But, unlike Delphi, Croesus would not benefit. He next sent a messenger to ask, would he succeed in a war against Cyrus?
The oracle’s answer is one of the most famous predictions in history. Pythia advised:
If Croesus made war on the Persians, he would destroy a mighty empire.
Herodotus, I, 53.
Croesus without delay mobilised his forces to march against the Persian empire. Crossing the Halys, he seized and plundered a key fortress. Cyrus and his forces arrived and the two armies fought to a stalemate. Croesus, believing he had put Cyrus in his place for now, retreated back over his border and disbanded for winter. No one fought in winter.
But Cyrus was not one to wait about. He launched into Lydia, routing Croesus’ army and besieging Sardis. In a desperate final battle, fighting to save his own skin, Croesus was captured and dragged before the Persian Shah of Shahs. The once-mighty Lydian was sentenced to be burnt alive, tied to his own gilded throne.
Only now did the realisation finally sink home; he had missed a critical ambiguity: the empire he would destroy was his own.

Pythia’s prediction had driven Croesus to gamble his entire kingdom, and lose. His defeat was to have a lasting impact through ancient history. Success brought great wealth to Persia, inspired Cyrus and demoralised his enemies; in the coming decades Persian armies would march across the western Mediterranean and Levant, forming the superpower of the ancient world. Lydia had been an important buffer state between central Asian empires and the fractious world of the Greek city-states. Over the next seventy years Cyrus and his successors would conquer Babylon, take Egypt, and invade Greece twice.

With Persian supremacy boosted by Pythia’s fateful prophecy, you might think leaders would be wary of oracles bearing cryptic advice. You would be wrong. The Gods were dangerous beings to deal with, but the surety of divine help to navigate an unpredictable world was too tempting. As legend grew around Pythia’s ability, more and more emissaries of kings, emperors and assemblies would seek her sanction for new rulers, colonies, law codes, wars, and peace treaties. In Sparta her pronouncements legitimised the kings and their heirs, and across the Mediterranean she launched colonies and conflicts. Pythia’s advice would leave a mark on countless lives and change the course of history. Wars would be fought to control access to Delphi and the oracle’s pronouncements.

An even greater irony may hide beneath the story that made Delphi’s reputation as a player in high politics. Perhaps Croesus’ story has been intentionally warped.
Some historians have suggested it is much more likely the oracle gave Croesus an unambiguously positive prediction of success against Persia. This created a problem for ancient storytellers and historians, keen to make the narrative more sensible after the events. How could Apollo have been so wrong? Surely greed had driven the wealthiest man in the world to overreach? Meanwhile, the Delphians were keen to downplay the error.
Pre-modern history often offers a natural symmetry where transgressions are punished and the just triumph. Such morality fables are the kind of stories humans seem attuned to seek; they help us weigh up our own decisions and make predictions about how others will respond. In time the ambiguous prophecy may have slipped into the story, stitching together a narrative that saved Delphian pride, confirmed Apollo’s power, damned Croesus’ campaign, and pleased its audience.
If so, Delphi’s triumph is built on Pythia’s failure.
Given the clout of the prophetess at Delphi, historians have long argued over how much understanding and resources she brought to bear on her predictions. Was Pythia offering sound political advice drawn from local knowledge, or working from intuition and whim? Some have even argued that her predictions were based on drug-induced hallucinations.
Hampered by the limited historic record and archaeological evidence for the ancient period, the modern theories remain uncertain.
For the ancient writers, the source of Pythia’s divine inspiration was clear: Apollo’s own breath rose from the fissure beneath her. As she sat on her tripod in the inner sanctum, breathing in his breath, the God himself possessed her. Pythia’s prophecies were issued in the first person; Apollo spoke directly through her. Her statements were interpreted by the male priests, the prophetes, who translated them into poetic verse and delivered them to the petitioners.
They say that the seat of the oracle is a cave that is hollowed out deep down in the earth, with a rather narrow mouth, from which arises breath that inspires a divine frenzy; and that over the mouth is placed a high tripod, mounting which the Pythian priestess receives the breath and then utters oracles in both verse and prose
Strabo, Geography, 9.3.5. Source: Persus Digital Library
The sweet-smelling “breath” rising from the fissure gained new significance in the late 1800s as medical anaesthetics came into popular use. The early anaesthetics, nitrous oxide, ether and chloroform, were all sweet-smelling gases, intoxicating and hallucinogenic when inhaled in low concentrations.
From the 1890s, French archaeologists excavated the ancient ruins. They found no great chasm or evidence of volcanic activity. Just as scientific advancements in medicine and geology were offering a possible mechanism for intoxication by volcanic vapours, French findings threw cold water on the matter for a century.
The other ways of thinking about the Delphic oracle fall broadly into two camps: cynical or true believer.
The cynical theory goes that Delphic officials were closely informed on political affairs and offered strategic, thoughtful, but sometimes self-serving predictions. Officials knew the questions well in advance. The oracle was either party to the scam or gave whatever ambiguous imagery came to mind. The priests adapted these to suit a pre-chosen answer. In this view Delphi operated as an biased ancient think-tank, sometimes providing thoughtful predictions and advice for decisions of state and sometimes advice that advanced Delphian interests.
The true believer theory goes that the Delphic officials and Pythia were impassioned servants of Apollo. The oracle gave whatever response came to mind, the prophetes shaped this into an interpretation befitting the question. If this were right, while the prophet and priests might layer on some personal bias or belief subconsciously, the predictions should offer little consistency.
To find the truth, two classicists, Parke and Wormell, trawled through ancient texts for decades to locate and analyse the Delphic prophecies for consistent patterns in political alignment. They carefully filtered out as best they could the prophecies they thought likely to have been doctored or imagined.
They found the advice given was practical, based on consistent religious and moral principles. This can be explained either by conscious intervention or that the questions provided by the oracle were likely loaded by the petitioners, who were seeking divine sanction for a pre-composed decision. There are also patterns indicating political biases and self-serving predictions, which points us towards the cynic camp.
The question boils down the same one we would like to honestly know of modern spirit mediums: are they deliberate deceivers, or merely self-deceiving? In that light, the example of Croesus can go either way. Either the Delphians were cagily hedging their bets with the ambiguous answer which was right – as either way an empire would fall. Or, they were giving the Lydians just what they wanted to hear – better a happy customer. Or, the idea simply popped into Pythia’s head on the day.
A neat synthesis of these views arrives when you consider the religious convictions of day. Few modern spirit mediums are true frauds. Most likely everyone at Delphi truly believed Apollo could enter and inspire Pythia. The priests further believed that in translating Apollo’s words into poetic verse they were experiencing a shadow of that inspiration. The priests and Pythia carried with them into the temple a sense of what answer the petitioner was likely seeking, their own moral convictions, and the political interests of Delphi. Thus prepared, the priests were almost always pleased to find themselves able to reassemble Pythia’s pronouncements to point towards an answer consistent with that which they hoped for.
So, what about the drug theory?
In 2002 a multi-disciplinary team published a controversial paper reviving the extraordinary idea that the ancient Pythia may have been inspired by huffing hallucinogens. They found evidence of geothermal activity and trace quantities of intoxicating gases, including ethylene, in a nearby spring. Ethylene is a close relative of ether and was used as common anaesthetic until the early nineteenth century. Low concentrations of ethylene and other mind-altering petrochemicals released through fissured porous limestone beneath the temple floor could have oozed into the inner sanctum of the temple: fuel for Pythia’s visions.

But the fumes remain frustratingly elusive. The substances found are common and the quantities minuscule. They may have dissipated over the centuries, but further tangible evidence is lacking. To have an effect, the gases would have been concentrated enough to be flammable. But there is no record of explosions at the site.
While tempting, the historic references to pneuma, variously translated as “breath”, “fumes” and “vapor”, are hard to lean on as evidence. The Greeks had no real understanding of gas. These terms are best understood in the context of ancient Greek philosophy where they are used so liberally they describe many invisible mechanisms, including the then unknown forces that made blood flow or the earth fill with minerals.
As many classicists have argued, while an intoxicated Pythia may offer a satisfying explanation, it papers over the gulfs in thinking between modern and ancient cultures. Perhaps the boundless faith of the centuries of pilgrims to the site and phenomena of oracles is best understood in context of the immense power of psychological suggestion and belief:
If you tell an elderly peasant woman that on a certain day, at a certain time, she will become the mouthpiece of Apollo, you do not need to be a hypnotist to get the desired result.
Hugh Lloyd Jones, The Delphic Oracle (1976).
Recommended Reading
Spiller, Henry, John R Hale, and Jelle Z De Boer. ‘The Delphic Oracle: A Multidisciplinary Defense of the Gaseous Vent Theory’. Journal of Toxicology. Clinical Toxicology 40 (1 February 2002): 189–96.
Lehoux, D. ‘Drugs and the Delphic Oracle’. Classical World 101, no. 1 (2007): 41–56.
Further References
Herodotus. Histories. Loeb Classical Library, 1952. Accessed June 2020.
Siculus, Diodorus. The Library of History, Book XVI. Loeb Classical Library, 1952. Accessed June 2020.
Polyaenus. “Cyrus” in Stratagems of War. Translated by R. Shepherd. London: George Nicol, 1793. Accessed June 2020.
Arnush, Michael. ‘Pilgrimage to the Oracle of Apollo at Delphi: Patterns of Public and Private Consultation’. In Pilgrimages in Graeco-Roman and Early Christian Antiquity, edited by Jan Elsner and Ian Rutherford, 97–110. Oxford University Press, 2005. Accessed June 2020.
Dodds, Eric R. The Greeks and the Irrational (1951): 68 – 76.
Lloyd-Jones, Hugh. ‘The Delphic Oracle’. Greece & Rome 23, no. 1 (1976): 60–73.
Luckhardt, Arno B., and J. B. Carter. ‘Ethylene as a Gas Anesthetic’. Anesthesia & Analgesia 2, no. 6 (December 1923): 221–229.