As you may know, behind Aeternum is a small business based in Brittany (in southern Finistère, to be precise). And it is well known that this region lives to the rhythm of legends, myths, and more or less well-known magical practices (Brocéliande, Merlin, the Fairy Viviane, the Alignments, and many others). Thus, to showcase our beautiful region, we will regularly publish little-known legends from Breton history.
This week, we are heading to northern Brittany, to the town of Tréguier, to discover the legend of the Serpent King. This legend is based on the collection Fifth Report on a Mission in Lower Brittany. A brief clarification: Lower Brittany comprises the entire western part of Brittany (Côtes-d'Armor, Finistère, and Morbihan), while Upper Brittany comprises the entire eastern part, at a time when the map of the territories was very different from today.
Long ago, a prince of Tréguier had an only son. Tired of living with his father, the young man wanted to travel throughout Brittany. The old king gave him a large sum of money, but his son quickly spent it on games and pleasures, leaving himself penniless and destitute. After a long journey, exhausted and hungry, he reached an isolated cottage. The owner, a rather poor tailor, offered him hospitality and new clothes. Revived, the young man continued his journey and arrived at an old castle in the heart of a forest. He entered and met an old woman leaning on a stick, who also offered him shelter for the night. Before he left, she warned him not to open one of the doors in the castle, assuring him that he would find something frightening behind it.

“Go quickly into the forest, cut a sturdy stick, and come back here. I will tell you what to do next.” The prince discreetly went into the nearby woods, cut a hazel stick, and returned to the serpent.
“Put this stick in my mouth and carry me silently on your back while the old woman is asleep. Walk straight ahead until you find another castle. If you feel tired, hungry, or thirsty, lick my mouth to regain your strength.”
The prince followed the serpent’s instructions to the letter and left the castle, carrying the serpent on his back. He walked for a long time, a very long time, and whenever he felt exhausted, he licked the serpent’s mouth, which was full of foam, with some apprehension, but he regained his strength. Finally, he spotted a castle surrounded by high walls in the distance. “That’s it!” said the serpent. “Courage!”
Upon reaching the courtyard, the serpent asked the prince to set him down and carefully remove the stick. As soon as the prince did so, the serpent transformed into a rather old man, but not an ordinary man: a king! In this castle, his three daughters, enchanted for five centuries, were waiting for him. At the sight of their father, they cried out with joy and quickly came down to embrace him.
The king then introduced the prince of Tréguier to his daughters, expressing the wish that one of them would marry him as a reward for his bravery. The two elder daughters rejected the idea without even thinking, but the youngest willingly accepted, grateful that he had freed their father. Her sisters, angry at the youngest’s decision, insisted that the prince prove his worth, which the old king approved.

The king gave the prince an enchanted sword and a beautiful white horse: “Go to Russia with these two companions. The horse will carry you, and as long as you hold the sword, you will have nothing to fear. You will arrive in the middle of a battle. Charge into the thick of the fighting, wield the sword while wishing for the death of the emperor of Russia’s enemies, and everyone who sees it will fall dead. The emperor, grateful, will offer you the hand of his only daughter. ”
The king warned him: “ But she will betray you with one of her father’s generals, her lover. Do not despair, for one day you will marry my daughter. When you are married, the daughter of the Russian emperor will steal your sword, and you will be put to death by her and her lover. Before you die, ask that your remains be placed in a sack, loaded onto your horse, and set free. The horse will return here, and I will bring you back to life with my miraculous water.”
The prince set off for Russia, accompanied by his magic sword and faithful horse, and everything happened as the Serpent King had predicted. He won the battle against the emperor’s enemies and married his daughter. He revealed the secret of his sword to his wife, and she stole it with the help of her lover. The prince was put to death and, in accordance with his last wish, his remains were placed in a sack that his horse carried back to the Serpent King. The latter used his water of life to resurrect the prince.
Three days later, the Serpent King announced to the prince that he had to return to Russia, this time in the form of a horse. “I will place a vial of my water of life in your left ear. When you arrive at the emperor’s court, go directly to the stable. A young girl named Souillon, mistreated but of noble birth, will come to your aid. She will say to your former wife, now remarried: ‘Madam, look at the beautiful horse that has just arrived!’
Your wife will order that you be killed and your remains thrown into a furnace. Souillon will protest, stroke your ear, and very softly, ask her to take the vial from your left ear. She will know what to do with it.”

The prince of Tréguier returned to the court of the Russian emperor, transformed into a magnificent horse. Upon seeing him, his former wife ordered that he be killed, chopped up, and his remains thrown into a blazing furnace. But Souillon, having already taken the vial of water of life from the horse’s ear, collected some of his congealed blood and placed it on a stone in the sun beneath the princess’s window. She sprinkled it with a few drops of the miraculous water, causing a cherry tree bearing magnificent red cherries to appear. The princess, believing this to be a sign from her first husband, ordered the tree to be cut down and burned. However, Souillon had kept one cherry, which she placed on a stone and sprinkled again with the water of life. A beautiful blue bird appeared and flew away chirping. The princess and her husband tried to catch it, placing the sword on the ground. The bird then landed on the sword, resuming its human form: it was the prince of Tréguier!
He seized the sword and exclaimed: “Everything is fine!” Then he beheaded his wife and her lover. The prince then returned to the Serpent King, accompanied by Souillon, who in fact turned out to be the youngest of the three daughters, serving the emperor because of the powerful spell that had transformed her father into a serpent.
Thanks to the prince’s bravery, the king and his daughters were freed from the power of the magician who had enchanted them for five centuries. The prince married the youngest princess, celebrating their wedding with splendid festivities.
And so this week’s legend comes to an end. See you next week!






























