Lludd son of Beli was a good king of Britain. He rebuilt the walls of London so well that the city was called Caer Lludd after him — Lludd's Gate, some say, is an echo of that name. His brother Llefelys had crossed the sea and married the heiress of France, becoming king there. The two loved each other, which is rarer among royal brothers in the old tales than you might think. And it was just as well, because Britain was about to need both of them.
Three plagues fell on the island. The first was a people called the Coraniaid. They were so sharp of hearing that any word spoken anywhere in Britain, if the wind caught it, reached their ears. No plan could be made against them, because they heard it being made.
The second was a scream. Every May Eve, a shriek went up over every hearth in Britain, so terrible that men lost their colour and strength, women lost their unborn children, young people lost their wits, and animals, trees, earth and water were left barren.
The third was a vanishing. However much food was gathered in the king's courts — even a year's provisions — it was all gone by morning, and no one ever saw who took it.
Lludd sailed to France to ask his brother's advice, and Llefelys, knowing the Coraniaid would hear them, had a long bronze horn made so the two could whisper through it. Even then, a demon in the horn twisted their words into insults until they poured wine through it to drive it out.
Then Llefelys gave his counsel. For the Coraniaid, he gave Lludd a kind of insect to crush in water: the water would kill the Coraniaid and harm no one of Britain. Lludd called everyone together, sprinkled them all, and the invaders died.
The scream, Llefelys said, was a dragon — the dragon of Britain, fighting every May Eve with a foreign dragon trying to overcome it, and shrieking as it fought. Lludd must measure the island and find its exact centre. That turned out to be Oxford. There he dug a pit, placed in it a vat of the best mead, and covered it with silk. The two dragons fought above it, first as monstrous beasts, then as two small pigs, and at last sank exhausted onto the silk and into the mead, where they drank and fell asleep. Lludd wrapped them in the silk, locked them in a stone chest, and buried them in the strongest place in his kingdom: a hill in Eryri, later called Dinas Emrys.
The captured dragons were later buried at Dinas Emrys, where they become the red and white dragons of the Merlin story.
The thief of the feast was a giant magician who lulled the court to sleep with music. Lludd kept watch beside a vat of cold water, plunging his head in whenever he grew drowsy, and when the giant came with his great hamper, the king fought him and made him swear loyalty.
Centuries later, in another story, a boy called Emrys — Merlin — would tell King Gwrtheyrn why his tower at Dinas Emrys kept falling down: two dragons, red and white, sleeping in a pool beneath the hill. Wear Lludd and Llefelys and you wear the very beginning of that tale: the moment Britain's red dragon went into the earth, waiting to wake.