Another piece of Valyrian steel has entered the ring in Westeros but this small weapon has a tarnished history. Who does the dagger belong to on Game of Thrones? Littlefinger gave Bran kind of a shady gift.
It's normal to give someone a weapon that was used to attack them, right? Bran's new demeanor as the Three-Eyed Raven may be a little on the strange side, but he didn't deserve this. Plus, Sansa is right — Petyr Baelish is not a charitable man. He clearly wants something from Bran. If I were to guess, I'd say that the dagger was hush money for all of the secrets Littlefinger needs kept. He's done more than one dirty deed.
The "previously on" provided a quick reminder of the dagger's history, but let's parse through it. In the pilot episode of Game of Thrones, Bran witnessed Jaime and Cersei having sex in a tower, and the Kingslayer pushed Bran out of the window, hoping that the fall would kill him. Their incestuous relationship was proof that Robert Baratheon had no legitimate heirs, which was a major problem for the Lannisters and their position of power in Westeros. However, as we know, Bran did not die — though he also suffered memory loss. Even so, an assassin was sent to kill the boy when he was sleeping.
His mother Cat fought the anonymous man off, and seized this Valyrian steel dagger. She then set off to discover who had tried to kill her son. At King's Landing, Petyr Baelish admits that the dagger once belonged to him. It was a gift from King Robert. He then claims to have lost the dagger to Tyrion Lannister. However, Tyrion denies that and Jaime suspects that Littlefinger lost it to Robert — which if anything means that Cersei or Joffrey took it and sent the cutthroat. Weird that there are still unsolved mysteries left over from Season 1, isn't it? Bran asked Littlefinger if he knows who it was, and to the audience at least it's a genuine question.
However, the most important thing is that after betrayed Ned Stark, Littlefinger took the dagger from him. In that, I believe, lies Baelish's big mistake in giving it to Bran. The Three-Eyed Raven should be able to see the events that lead to Ned's arrest and beheading. He should probably tell Sansa and Arya that so that they can do their thing. Maybe Arya can use it on Littlefinger, even. Then again, maybe Bran would just prefer to talk about his family's various other traumas. Get it together, kid.
Not only is the dagger Valyrian steel, it looks an awful lot like one that Sam encountered in a book at the Citadel. This item is clearly significant, and will be important in the war to come. The fact that it has such a twisted and mysterious history makes it even cooler.