Python was born from Gaia, the primordial Earth, who had been coated with the slime and mud left behind after Zeus, the king of the gods who rules from Olympus, sent the great deluge to destroy the race of men. From that warm, rotting earth, Gaia brought forth a serpent such as the world had never seen, a drakaina with a woman's head and breast and a serpent's coils that stretched across the mountainside. The Greeks called her Python, from the word pytho meaning to rot, because she was born from decay and because her corpse would one day give the sacred place its name. She made her home in the caves beneath Mount Parnassus in Phocis, coiling around the omphalos, the stone navel that the Greeks believed marked the very centre of the world. Before Apollo ever came to Delphi, the oracle belonged to the earth itself. Gaia spoke first, then her daughter Themis, the Titaness of divine law, and then the Titaness Phoebe, another daughter of Gaia. Python guarded the shrine and the sacred spring, ensuring that no unworthy mortal approached the place where the earth's voice could be heard.

The serpent's path crossed with the gods even before Apollo drew his bow. When Leto, the daughter of the Titan Coeus, became pregnant by Zeus, Hera, the queen of the gods and Zeus's wife, was consumed with jealousy. She sent Python to pursue Leto across every land, forbidding any place to offer her shelter for the birth. The great serpent hunted the goddess for months, her jaws gaping and her three-tongued mouth athirst, until the wind Boreas, the north wind, carried Leto to the island of Ortygia, which Poseidon, the god of the sea, covered with waves to hide her from sight. There, clinging to an olive tree, Leto gave birth to the twins Artemis and Apollo. Python returned to her lair at Parnassus, never knowing that the infant she had failed to kill would soon be the instrument of her death. Some said she had been sent by Hera, others that she acted from her own malice, but all agreed that the serpent's pursuit of Leto sealed her doom.

Apollo was four days old when he set out from Delos to claim his oracle. He travelled with his mother Leto and his sister Artemis, the virgin huntress, to Mount Parnassus, where the serpent still coiled around the sacred stone. The young god, still beardless and rejoicing in his flowing locks, found Python at the Castalian Spring, the sacred fountain of Delphi, her bloated body sprawled across the hillside and her poison fouling the waters that the nymphs drank. She moved to block his path to the oracular cleft, for she knew that the son of Zeus had come to take what was hers. Apollo drew his bow, a gift from Hephaestus, the lame smith-god of Olympus, and let fly a volley of arrows. The shafts struck her again and again, a hundred wounds pouring black poison across the soil. She writhed and rolled, her coils crushing ancient oaks to powder, her gasps filling the wood with an awful noise. Darkness covered her eyes, and the holy strength of Helios, the Sun, made her rot away where she fell.

The killing of Python was no simple victory. Apollo had slain a child of Gaia upon her own sacred ground, and the earth was enraged. Zeus ordered the young god to purify himself for the sacrilege, and Apollo travelled to the Vale of Tempe in Thessaly, a gorge sacred to him, where the river Peneus washed away the blood-guilt. Some said the Cretans purified him instead, or that he came to Sicyon for cleansing. To placate the anger of the earth and to honour the fallen serpent, Apollo instituted the Pythian Games, athletic and musical contests held every four years at Delphi in memory of the monster he had slain. He buried her bones in a cauldron within his temple and placed her image upon his tripod. The priestess who spoke his oracles took the name Pythia, after the place that bore the serpent's name, and for a thousand years her cryptic verses would guide kings and cities. The serpent was dead, but her name lived on in every prophecy breathed from the sacred cleft.

For centuries, the image of Apollo slaying the serpent was carved into temple pediments and painted upon vases, the young god standing triumphant with his bow while the monster lay dead at his feet. The story became the founding myth of Delphi, the explanation for why the oracle belonged to Apollo rather than to the earth. The serpent's body sprawled across so many acres that it seemed to blight the land itself, and Apollo's quiver was nearly emptied before she finally stilled. The name Python passed into Latin and then into English, where it became the word for any great constricting snake. In the modern age, it names a family of serpents and a programming language, but its oldest meaning remains the rotting corpse of the earth-dragon whose death gave the world its most famous oracle.