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Caliburn: The First Legedary Sword of Arthur

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Caliburn is the name of King Arthur’s legendary sword in some of the Arthurian legends. It was a favourite weapon of his when engaging in battle against his enemies, such as the Saxons.

In modern writings, Caliburn has often been chosen as the name for the sword that Arthur pulls from the stone. However, there is not ancient text that supports this. In ancient times, Caliburn was just an early evolution of the sword Excalibur.

In this article, you will learn:

  1. Which legends feature Caliburn
  2. What the legends say about it
  3. What its name means
  4. What King Arthur did with it

And don’t forget to visit our Arthurian hub page, where you can learn a lot more about subjects like this one. You can also see our list of other Arthurian weapons and artifacts here.

What Was Caliburn?

Put simply, Caliburn was a special sword that King Arthur would wield in battle against his enemies.

According to Geoffrey of Monmouth, writing in c. 1137, Caliburn was forged in the Isle of Avalon. Famously, the Isle of Avalon was the location to which Arthur was taken after he was mortally wounded.

Right from its first appearance, Avalon seems to represent an otherworldly location. Therefore, Geoffrey’s statement about Caliburn seems to suggest that the sword had an otherworldly origin.

However, he never expands on this statement, nor explains how it came to be in Arthur’s possession. Later tales generally do not expand on this point either, if they even refer to it at all.

Furthermore, Caliburn is not portrayed as having overtly magical powers or abilities like certain weapons from other legends (such as the Gae Bolg from Irish mythology). It is usually just portrayed as an exceptionally effective sword. 


The name ‘Caliburn’ is written various different ways in the legends in which it appears.

In the earliest record which mentions it – Geoffrey of Monmouth’s Historia Regum Britanniae – it is spelt ‘Caliburnus’.

A different twelfth-century Geoffrey, named Geoffrey Gaimar, used the form ‘Caliburc’ in his Arthurian tale.

Wace, another twelfth-century writer, referred to Caliburn by several different names. He called it Callibourc, Calabrun, Caliborne, and Calibore, to mention just some of the variant spellings found.

Etymology of the Name

The reason why some of these alternative spellings end in ‘urc’ rather than ‘urn’ is revealed by looking at the etymology of the sword’s name.

Arthur’s sword features in several Welsh tales which predate Geoffrey of Monmouth, such as the tale known as Culhwch and Olwen.

In this story, written around the year 1100, Arthur’s sword is named ‘Caledfwlch’. This name is composed of two Welsh words.

The first part, ‘caled’, means ‘hard’.

The second part, ‘fwlch’, is a mutation of the word ‘bwlch’ and means ‘breach’ or ‘split’.

So the name ‘Caledfwlch’ refers to the sword being effective at cutting through things (which is certainly a good quality for a sword to have).

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Preservations and Changes From the Welsh Form

As we can see, the original spelling of the name of this sword ended with ‘ch’, not ‘n’. This is clearly the reason why writers such as Geoffrey Gaimar and Wace used spelling variations which ended in ‘c’.

They evidently had access to sources which better preserved the original Welsh spelling than Geoffrey of Monmouth’s ‘Caliburnus’.

But even in the spellings which preserve the final ‘c’, they still use an ‘r’ before it, not an ‘l’. What explains this?

Simply, this must be a corruption. The letter ‘l’ is very similar to the letter ‘r’, and there is another clear example in the Historia Regum Britanniae of Geoffrey making such a change.

He refers to the father of Peredur as being a man named ‘Eridur’. In Welsh records, the father of Peredur was named ‘Elidur’.

Evidently then, the change of an ‘l’ to an ‘r’ in the name ‘Caliburn’ is merely due to this simple corruption.

The change of the first part, ‘Caladb’, into ‘Calib’ may be due to influence from the Medieval Latin word for steel, ‘calibs’.

How Arthur Used Caliburn

Caliburn is mentioned by name a number of times in the Historia Regum Britanniae. Here are the different occasions on which it is used:

At the Battle of Badon

Caliburn first appears in the Historia Regum Britanniae during the description of the Battle of Badon. As Arthur and his men are preparing for the battle, Geoffrey mentions that Arthur girds his sword to his belt.

However, Arthur does not use it straight away. In fact, he uses a lance (which also has a name, ‘Ron’) during the first day of battle.

Partway through the second day of fighting, when Arthur reflects on the fact that his army is struggling to beat the Saxons, he finally decides to draw his sword.

As he does, he calls on the name of the Virgin Mary. The fact that he does this right as he draws his sword, and not earlier in the battle, perhaps points towards the supernatural nature of Caliburn.

With his holy sword, Arthur kills 470 Saxons. This feat in itself is so grand that it, again, indicates that he had divine backing while using this sword.

In the Duel with Frollo

Next, Caliburn appears during the climax of Arthur’s initial European conquest.

Frollo was the Roman governor of Gaul. Arthur invaded Gaul and attacked Frollo’s army. With most of the latter’s army switching sides, Frollo fled to Paris.

Arthur chased after him and besieged the city. Eventually, they arranged to settle the matter by having a jousting duel.

Arthur was able to knock Frollo off his horse. He then rode over to him and was going to kill him with his sword, when Frollo used his lance to kill Arthur’s horse, causing Arthur to fall to the ground.

The two men then engaged in combat with their swords, until finally Arthur was able to get a clean swipe at Frollo’s forehead. The blade of Caliburn went right through Frollo’s metal helmet and cut into his head, killing him.

Against the Giant of Mont Saint-Michel

When Arthur returned to Gaul years later, he faced a giant on Mont Saint-Michel. This was a much fiercer battle than the one against Frollo.

Arthur again tried to strike his enemy in the forehead, but it was not a fatal blow. But later on in the struggle, Arthur managed to push Caliburn right through the giant’s head, killing him.

At the Battle of Siesia Against the Romans

The climax of Arthur’s entire European campaign took place at the Battle of Siesia against a large army of Romans and barbarian nations.

Seeing his men in great difficulty (for Arthur had stayed back for most of the battle), Arthur charged at the enemy with Caliburn drawn.

The account tells us that Arthur killed everyone he passed with a single strike with his sword.

Caliburn in Modern Media

Caliburn has appeared in modern media, although Arthur’s sword usually appears under the guise of Excalibur. Some examples in which Caliburn appears are:

  • Sonic and the Black Knight: This 2009 game, developed by Sonic Team, features Caliburn as a talking weapon that instructs Sonic.
  • Fate/Grand Order: This 2015 mobile RPG by TYPE-MOON features Caliburn as weapon.

Frequently Asked Questions About Caliburn

Is Caliburn the Same as Excalibur?

Yes, Caliburn and Excalibur are the same sword. They are simply different spellings. In fact, Wace’s Roman de Brut features the alternative spellings ‘Caliborne’ and ‘Escaliborc’ for Arthur’s sword.

What is the Difference Between Excalibur and Caliburn?

‘Caliburn’ is the name of Arthur’s sword in the Historia Regum Britanniae and other medieval romance tales. This name gradually evolved into ‘Excalibur’.

The tales which use the name ‘Excalibur’ usually present the sword in a somewhat different way to how Caliburn is portrayed, simply due to the fact that the Arthurian tales themselves continued to evolve as the name of the sword did.

Therefore, Excalibur is usually said to have come from the Lady of the Lake, while Caliburn, earlier, was said to have been forged in the Isle of Avalon.


This depends on the author. In the earliest texts after the introduction of the Sword in the Stone, there does not seem to be a distinction between this and the sword called Caliburn. However, in more later writings, Caliburn is often relegated to being the Sword in the Stone, whilst Excalibur is later gifted by the Lady of the Lake.

Arthurian Bibliography

See also my ever-expanding list of primary and secondary sources.

Photo of author


Caleb Howells is a writer from the south coast of England. He has spent years researching various different myths and legends from around the world, with his primary area of interest being the legends of King Arthur. In May 2019, Caleb published King Arthur: The Man Who Conquered Europe, outlining his theories on the origin of the legend.

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