- "Ser Arthur Dayne, the Sword of the Morning... led the attack on the Kingswood Brotherhood. Defeated the Smiling Knight in single combat."
- ―King Joffrey Baratheon
The Smiling Knight was a prominent member of the outlaws called the "Kingswood Brotherhood" and was mentally imbalanced. Ser Arthur Dayne while leading the Kingsguard in suppressing the outlaws, fought him in single combat. During the duel, the sword of the brigand was sheared in two and Ser Arthur allowed him to call for another sword. The Knight however, was slain in the duel, ending the threat of the Kingswood Brotherhood for good.
In the books
In the A Song of Ice and Fire, novels the Smiling Knight was an infamous outlaw reputed to be insane as well as a deadly swordsman. Jaime Lannister describes him "a madman, cruelty and chivalry all jumbled up together, but he did not know the meaning of fear." Jaime compares him to Gregor Clegane, calling him "The Mountain of my boyhood". At some point during his career he killed Ser Victor Tyrell, cousin of Lord Mace Tyrell of Highgarden.
During the combat between the Brotherhood and the Kingsguard, the Smiling Knight briefly crossed swords with Jaime Lannister, but Jaime held him off. Arthur Dayne next fought an extended exchange with him until the Smiling Knight's sword broke. Dayne paused the fight and allowed the outlaw to take a fresh sword. The Smiling Knight did so, but remarked that it was Dayne's famous sword Dawn that he truly desired. In the second exchange, the Smiling Knight was killed. His death is considered Arthur Dayne's most famous accomplishment