After an embarrassing encounter with Duncan during PAX East (HOW DID I FORGET YOUR FACE), my old ass thread was discussed. Mainly, we talked about reposting it here. So that's what I'm going to do.

In Marathon, we've got Durandal and in Halo there's Cortana. In a mix of European history and mythology, these are the names of swords that were carried by prominent men.

Ogier the Dane was the holder of Curtana. Count Roland wielded Durendal until his dying breath.
Stay with me, I am arriving to a point.

On Curtana's blade there's an inscription:

My name is Cortana, of the same steel and temper as Joyeuse and Durendal.

So, where's Joyeuse? In Destiny.

he swords, Durendal and Curtana represent the A.I. characters Durandal and Cortana. The events surrounding the AI characters are basically metaphors for the events surrounding the swords.

In turn, the story of Master Chief parallels that of Ogier the Dane, and MJOLNIR Recon Number 54 (not the moderator) parallels Count Roland.

Not only do these stories parallel, they interact with each other. These men became allies to combat the invading Saracens and Charlemagne (see below) even used Joyeuse to knight Ogier the Dane.

If this tradition is to be followed, then your protagonist will parallel Charlemagne and his sword Joyeuse. Plot points, character names (specifically your AI sidekick) and character development can be traced back to Charlemagne and his sword.

In short, that's all you really need to know if you're not up for reading. But if you want proof, here you are:

MRN54 vs. Count Roland & Durandal vs. Durendal
Note: More detailed evidence may be found in the original thread.

The parallels here are more about the protagonist's interactions with his sword/AI.

In the "Song of Roland", Count Roland, faced with defeat during the battle of Roncesvalles, attempts to destroy his allegedly unbreakable sword, in order to keep such a weapon away from the enemy. He strikes his sword against a cliff, only to destroy part of the cliff, while his sword remains whole.

Remind you of anyone, Marathon players? Durandal instructs the player to destroy him in order to avoid Leela's fate of being captured by the Pfhor. (Keep in mind that this was not an honest request made by Durandal. He's a sneaky bastard.) After you destroy Durandal, it turns out that he remains unscathed and endures on throughout the trilogy. (The only thing that actually destroys him is the literal end of the universe... It's complicated.)

I'd like to top this off with the fact that Durandal makes direct references to Count Roland, Charlemagne, and the sword Durendal.

Master Chief vs. Ogier the Dane & Cortana vs. Curtana

Ogier the Dane is a legendary character in Danish mythology. He was the son of the king of Denmark. According to legend, mere days after his birth, he was visited by six sister maidens (this is extreme paraphrasing, by the way) who granted him the promise of becoming the greatest warrior of his time and plenty of chances to prove it.

Ogier was given the sword Curtana, which was originally Tristan's sword. The sword was shortened to fit Ogier.

Ogier's son was killed by the kin of Charlemagne, igniting a hatred inside Ogier that led him to hunt down his son's killer and Charlemagne himself. Ogier got his revenge, but was barely prevented from killing Charlemagne.

In order to defend his people and take down a threat that threatened both him and Charlemagne, Ogier makes peace with Charlemagne and Count Roland in order to defeat the Saracens.

When the struggle was over, Ogier went to sleep under castle Kronborg. When his people were under threat once more, Ogier said that he would rise once more to deliver his people from the threat.

Like Ogier, John-117 was raised to become an excellent warrior, and with the internal conflict amongst humanity, he was guaranteed to prove his skills. Cortana also went through a bit of a "shortening" before landing in MC's hands. This is a vague parallel, but the copying/splitting she underwent on Reach may parallel Ogier's sword being shortened before going to him.

Before finding the Flood, he lost many of his fellow Spartans, colleagues, and friends to the Covenant. But in order to, not only save humanity, but all life, he had to make peace with the Arbiter and the elites. When the fight was finished, the Master Chief went back into the cryo tube to sleep, after instructing Cortana to, "wake me when you need me."

Joyeuse and Charlemagne
This is where details get thin. I don't have an actual character or AI to compare to Charlemagne or his sword. The AI section of figure four is blank for a reason. I don't really have anything.

Charlemagne was basically the father of Western Europe. He was king of the Franks and ushered in many reforms during his reign. Things to note are:

• he co-ruled with his brother. They did NOT get along, and the only thing that prevented war was his brother's convenient death.
  
• he carried on his father's policies and removed the Lombards from power in Italy.
  
• he waged war in Spain against the Saracens.
  
• he fought alongside Ogier the Dane and Count Roland during the battle of Roncesvalles, where he experienced the worst military defeat of his life.

As for his sword, Joyeuse was used to behead a Saracen commander and to knight Ogier the Dane. See figure four. The problem here is, again, I have no idea which details about this man or his sword will matter.

Joyeuse in Destiny (So Far)
(I swear, I'll provide links later. This is the third time I've tried to post this thread. Firefox loooooves to crash. I'm switching to Chrome, I swear)

Recall that a mission to retrieve an AI named Charlemagne was described during the time of the initial reveal. The AI Charlemagne may be named after its creator or previous owner. Perhaps it goes by another name, like Joyeuse?

Additionally, there's the legend of a nameless knight retrieving the sword Joyeuse, which was lost in battle. Charlemagne rewarded this knight was a boon-- the town of Joyeuse in France. Perhaps that mission parallels the legend? Maybe we're the nameless knights, and not Charlemagne? This opens up plot possibilities, and no longer ties the writers down to Charlemagne's story.

I am of the opinion that this formula doesn't necessarily tie anyone down, though. It simply provides guidance and plot point ideas, allowing the writers more time forge details around the general plot.