Warning: Major spoilers for The Winter King season 1 episode 6 below!

Summary

• In episode 6 of The Winter King, Merlin has a vision of the Horn of Bran, one of the legendary treasures of Britain.
• Merlin embarks on a quest to retrieve the Horn of Bran, believing that if he can find it, he can also find the other treasures.
• If Merlin and his allies can recover all the treasures, they believe it will give them the power to reclaim Britain.

The Winter King show cast Nathaniel Martello-White as Merlin, where he acts as a mentor to Arthur (Iain De Caestecker) while often disagreeing with his decisions.

For the first half of season 1, magic hasn't played much of a role, though Merlin's "Death of Britain" visions certainly suggested bad things to come. The sixth episode digs a little deeper into Merlin's abilities, as he decides to set out on an adventure to retrieve an important object. He also confirms to Arthur that his new sword is Excalibur and that Merlin himself brought it over from Ireland years before; the fact it found its way into Arthur's hands makes it seem like the Gods really wanted him to have it.

The Winter King's Horn Of Bran & Merlin's Quest Explained

Merlin has been lacking in subplots for much of Winter King season 1, aside from an ill-advised attempt to kidnap baby Mordred. The heir to the throne of Dumnonia is, according to Merlin's visions, destined to become a bloodthirsty tyrant who will lead to the end of Britain. Merlin thus tried to take Mordred and planned to drop him off at a village, where he would be raised with no idea of his royal heritage. Arthur foiled this plan, but episode 6 gives Merlin a new task. He has a vision of entering a snowy cave, where he discovers the Horn of Bran.

This is said to be one of the fabled Thirteen Treasures of the Island of Britain, which are a series of magical items found in Welsh manuscripts that date back to the 15th Century. The Horn of Brân Galed from the North is said to be filled with whatever drink a person desires; so if they want an endless supply of wine, the horn will provide it. Merlin sets out on a quest to the wilderness in the North to recover the horn and believes that if he recovers it, he can find the other treasures too.

What Are The Other Treasures Of Britain?

The manuscripts always state that there are thirteen treasures of Britain, though some texts change what those items are. Some even list Arthur's sword Excalibur among those magical objects. Here are the rest of the Thirteen Treasures of the Island of Britain:

White-Hilt, the Sword of Rhydderch Hael the Generous - It's said that if a well-born man draws this sword, it would ignite in flame. Rhydderch was one of the Three Generous Men of Britain and was always willing to hand the sword over to those who asked. However, nobody ever asked when they learned what it did.

The Hamper of Gwyddno Long-Shank - A hamper that is said to multiply the food placed into it a hundredfold.

The Chariot of Morgan Mwynfawr (AKA the Chariot of Morgan the Wealthy) - A special chariot that will take someone wherever they wish to go really quickly.

The Halter of Clydno Eiddy - Also known as The Handy Halter, this will summon whatever horse a person wishes for in the halter.

The Knife of Llawfrodedd the Horseman - A knife that is said to serve up to 24 men at a table.

The Cauldron of Dyrnwch the Giant - A cauldron that distinguishes the brave from the cowardly. So if a brave man puts meat in the caldron, it will boil fast. However, if a so-called coward puts meat in, it wouldn't boil at all.

The Whetstone of Tudwal Tudglyd - Once again, an object to separate the strong from the weak. If a brave warrior sharpened their sword on this whetstone it would kill anyone it drew blood from; if a coward did the sharpening, their sword wouldn't even draw blood.

The Coat of Padarn Beisrudd - Yet another item that discriminates against cowards. This coat will fit those who are brave, but it won't fit weaklings.

The Crock and Dish of Rhygenydd Ysgolhaig - Similar to the Horn of Bran, this will serve whatever food a person desires.

Chessboard of Gwenddoleu ap Ceidio - A large golden chessboard where if the pieces (which are made of silver and crystal) are set up right, they'll play themselves.

The Mantle of Arthur in Cornwall - This renders anybody under it invisible, but it allows them to see out.

The Stone and Ring of Eluned the Fortunate - A ring that Merlin already seems to possess in Winter King. Like the aforementioned Mantle of Arthur, this renders the wearer invisible.

What Happens If Merlin Recovers All The Treasure In The Winter King

Merlin believes that if he retrieves the Horn of Bran - which Nimue (Ellie James) claims is the most difficult item to find - then the others will soon follow. If they complete this sidequest in The Winter King, Merlin claims the objects will give them back the power to reclaim Britain. That might be wishful thinking on his part, but it'll be interesting to see what happens if he can actually recover them all.