|The Mystery Knight (mentioned)
Mortimer was a knight of some repute as a jouster.
Ser Mortimer attended the wedding tourney at Whitewalls in 212 AC. He was defeated in the lists by Ser Glendon Flowers, and had to forfeit his horse and armor for his loss. However, because Glendon was a bastard, Ser Mortimer refused to send over his horse, and the armor he sent over had holes hammered through it.
Dunk: How many horses have you won?
Glendon: I lost count. Mortimer Boggs still owes me one. He said he'd rather eat his horse than have some whore's bastard riding her. And he took a hammer to his armor before sending it to me. It's full of holes. I suppose I can still get something for the metal.