'House of the Dragon': The Significance of the Song of Ice and Fire Dagger

In Episode 4 of HBO's House of the Dragon, King Viserys Targaryen gives viewers a close look of a special dagger made of Valyrian Steel.

The king reads to his daughter, Princess Rhaenyra, an inscription on the blade of the knife—visible when exposed to heat—that reads, "From my blood come the prince that was promised...and his will be the song of ice and fire."

The dagger holds a special meaning in Game of Thrones lore, and even many casual viewers know the original show is based on the fantasy novel series A Song of Ice and Fire by George R.R. Martin. Fans of the show have also seen the weapon before.

The Valyrian Steel dagger, often referred to as Catspaw among GoT admirers, played a crucial role in the original series. In fact, it was arguably the most important single weapon in the eight seasons of the Game of Thrones. Before it shone during its biggest moment in the final season, though, the knife journeyed down a long path.

Martin described Catspaw's origins as starting with Aegon I Targaryen, better known as Aegon the Conqueror. Aegon was the first Targaryen to rule over Westeros, and he was responsible for forging the famous Iron Throne from the swords of his fallen enemies using the fire of one of his dragons.

Aegon may have also forged the dagger—with its hilt made of dragon bone—as he is said to be its first owner. After his death, it was given to each of the succeeding Targaryen kings until Viserys. Since the events of House of the Dragon take place many years before Game of Thrones, viewers have already seen the knife on the latter show.

Targaryens are no longer in possession of the dagger by the time of Game of Thrones. It was revealed during the 2011 premiere season by an assassin, or Catspaw, who unsuccessfully attempted to kill Bran Stark.

Bran's mother, Lady Catelyn Stark, took possession of the dagger and set off to bring it to her husband, Ned Stark. On her way, she encountered Lord Petyr Baelish, aka Littlefinger, who told her the knife belonged to him before he lost it in a bet to Tyrion Lannister. Thus, Lady Catelyn mistakenly blamed the failed assassination attempt on House Lannister, but Littlefinger is later blamed for hiring the Catspaw.

Ned Stark momentarily held on to the dagger until his arrest, at which point Littlefinger reclaimed it. Baelish later gifted it to Bran, who in turn gave it to his sister, Arya. After the accusations are made against Littlefinger, Arya used the dagger to kill him.

Before the blade is used to kill Littlefinger, though, it was referenced during Samwell Tarly's time at the Citadel, where he reads a book's passage describing the Valyrian Steel dagger and how Aegon and his descendants would decorate weapons with dragon glass.

Perhaps the most important moment for the Catspaw dagger came during the final season of Game of Thrones after Winterfell's defenders learned Valyrian Steel was one of the few things capable of killing the invading White Walkers.

With that knowledge, Arya used the dagger to kill the Night King, who destroyed his army of White Walkers in the process. At the conclusion of Game of Thrones, Arya Stark was seen with the dagger as she set off from Westeros for new adventures.

The success of House of the Dragon could very well push along the development of other GoT spin-offs, including a sequel show based on Jon Snow's life. Should Arya appear again, it is likely the Catspaw, aka the Song of Ice and Fire dagger, will be with her.

House of the Dragon fans will certainly see the dagger again before any future GoT spin-offs, though. The knife was spotted by fans in the hands of Alicent Hightower in the show's first trailer released before the premiere.