Why Do Dragons Hoard Gold?
Nobody knows, and that is the interesting part. Greek, Norse, English and Germanic stories all agree that dragons lie on treasure, and not one ancient source gives a reason for it.
Consider how strange it is. Gold is not food. A serpent cannot spend it, wear it or eat it. Nothing about being frightened of a snake would lead you to imagine that the snake's main activity is lying on metal and refusing to move.
Yet in Greece, Ladon is coiled around the golden apples (Hesiod, Th. 333–336). In Scandinavia, Fáfnir kills his father for gold and lying on it is what turns him into a dragon. In England, the dragon of Beowulf holds a hoard inside a barrow for three hundred years and burns a kingdom over a single stolen cup.
The explanations offered are thin. Beowulf says the creature is glad of the treasure, which explains nothing about three centuries of it. Fáfnir's gold is cursed, which explains his end and not his behaviour. The Greek sources do not attempt it.
When several unconnected traditions report the same strange and pointless habit and none can account for it, the usual inference is that they did not each invent it.
In the Codex. The Codex gives a reason, which is the only ancient text that does.
Acenes of Sparta: The Dragon Slayer
A dragon is the reason the 300 died. Leonidas used the magic of the gods to bind Kalaxes beneath Taygetus, and the price was his life and his men's. Sixty-two years later a seven-year-old of the agoge falls into the dragon's crypt and inherits the unpaid balance.
Free to read with Kindle Unlimited. Open it on Amazon.