With a picture shared on its Facebook page, HBO Nordic confirmed the return of the Valyrian Steel Dagger we already saw on the cover of Entertainment Weekly. As many fans already know, Maisie Williams appeared on the magazine's cover in full Arya Stark's costume with the dagger. The Internet went immediately crazy about the blade's reappearance, but only a few people know the full and surprising story behind the weapon. Warning: mild spoilers on "Game of Thrones" season 7 will follow!

Someone tried to kill Bran with that dagger

Let's start with what happened in "Game of Thrones" season 1.

After Bran's fall from the Winterfell's tower, a catspaw entered Bran's room to kill him. Catelyn and Summer stopped and then killed the assassin, retrieving his Valyrian steel dagger. Shortly after, Littlefinger, who owned the dagger in the first place, told Eddard that he bet and lost the weapon to Tyrion Lannister and - if you think about it - this is the main reason why Catelyn decided to take Tyrion prisoner, event which led to the Stark-Lannister conflict.

The story behind the blade

Who owned the dagger when the catspaw went to Bran's chamber to kill him? Who sent the killer? The answer is going to surprise you. You may think that Cersei or Littlefinger paid the assassin, but they didn't.

The truth can be found in the "A Song of Ice and Fire" book series. In "A Game of Thrones" Littlefinger explains that he had once owned the blade, adding that he bet and lost it to Tyrion during the tourney on Prince Joffrey's name day when Loras defeated Jaime.

After Tyrion is taken prisoner by Catelyn, he insists to Lady Stark that he never, ever owned that blade.

In "A Clash of Kings", when Jaime is in the dungeon of Riverrun, Tyrion's brother admits to Lady Stark he threw Bran from Winterfell's tower, but he confirms that Tyrion would never have made such a bet with Baelish. Therefore, the dagger wasn't in Tyrion's possession. Jaime also adds that he saw the Valyrian steel dagger displayed by King Robert Baratheon during a feast, since it was Robert the one who won the bet Littlefinger was talking about, and when The Kingslayer tells Catelyn that he and Cersei didn't pay for the assassination, she believes him.

Who paid for Bran's assassination?

If Jaime, Cersei, Tyrion and Baelish (who didn't own the dagger at the time) didn't send the catspaw to Winterfell, then who did?

In "A Storm of Swords" both Jaime and Tyrion deduce that there was only one person who could have sent the assassin to Winterfell, and that person was Joffrey Baratheon. Tyrion realizes that Joffrey could have hired the assassin from the camp followers attached to the King's party which reached Winterfell, and that the young prince could have taken his father's dagger from the King's weapons stash.

What about the motivation? Joffrey was a cruel little monster, we all know that, but maybe he didn't decide to kill Bran out of mere cruelty.

In the books, when Cersei tells Jaime that King Robert, speaking of Brandon, once said in front of Joeffrey: "We kill our horses when they break a leg, and our dogs when they go blind, but we are too weak to give the same mercy to crippled children", Jaime thinks that his son may have hired an assassin as a misguided attempt to impress the King.

We cannot be 100% sure that Joffrey was the one who paid for Bran's murder, but this is by far the most plausible theory at the moment.

Don't forget: "Game of Thrones" season 7 will premiere on July 16.