The Homeric Hymn to Apollo tells the killing of Python as one of the god's first acts, undertaken while he is still, in narrative terms, barely more than newly born, searching the Greek landscape for a place to establish his own sanctuary and oracle. He finds the spring at what will become Delphi already guarded, or rather terrorized, by a monstrous she-serpent the hymn calls Python, a creature blamed for killing flocks and travelers alike and generally making the region uninhabitable for the ordinary business of pasturing animals or passing through safely. Apollo does not negotiate or attempt to drive the serpent off; he shoots it with his arrows outright, and the hymn lingers on the aftermath rather than rushing past it, describing the serpent's body left to rot in the sun at the very spot where Apollo's temple and oracle would then be founded.
The hymn draws a direct etymological line from that decay to the place's own name, deriving Pytho, an older name for Delphi, from the Greek word for rotting, and Apollo's own epithet Pythian from the same root, so that the god's most famous cult title is presented as literally naming his kill rather than as an unrelated honorific. The killing is treated in the hymn not as an act of casual violence but as a founding deed, the necessary clearing of a dangerous, monstrous obstacle that makes the site fit to become the most important oracular sanctuary in the Greek world, and Apollo's decisive, almost immediate willingness to fight the serpent is part of how the hymn establishes his character as a god of order asserting himself over a chaotic, monster-haunted landscape.