Just before Peredur comes to Arthur’s court a Black Knight shows up, challenges the honor of Arthur’s court, and humiliates Gwenhwyfar by spilling her cup of wine as he steals it. The scene seems to make no sense, going as it does from a confrontation about kingship to the simple theft of a cup and the accidental insult to Arthur’s queen.
Then Peredur arrives, a naive boy who doesn’t know what to expect. In his usual cruelty, Cei despises the boy. No one (no one? Not Arthur, Lancelot, Gawain, or a host of other “flowers of knighthood”?) at the court dares to chase after the Black Knight, so Cei sarcastically tells Peredur to go fetch the cup.
As the hero of course Peredur succeeds in his first task and sends the cup back. But really, what can the kingship, the theft of a cup, and insulting the queen have to do with one another? And if there is something there, why does it have anything to do with a boy who doesn’t even know how to put armor on?
So let’s start again and work under the assumption that the story has been distorted from something a little more historical. That means we need to start with the connections we know; a queen and a cup are both closely linked to the religious aspect of kingship. The Black Knight challenges Arthur’s right to be the king, steals the queen’s cup, and humiliates the queen in the process. This Black Knight episode is, then, a simple challenge to Arthur’s kingship. It’s the same as what happens when the queen is abducted in Le Chevalier de la Charrette, Iwein, and Dialogue Between Arthur and Gwenhwyfar. We can simplify the scene; the Black Knight could have told Arthur he didn’t deserve the throne and to prove it he stole the cup that symbolized his right to rule and humiliated his queen, the symbol of the land. The Black Knight couldn’t have been more direct if he’d slapped Arthur with a glove.
So why doesn’t Arthur go out and defend his own honor? For the same reason that Lancelot rescues the queen in Le Chevalier de la Charrette; a new hero is given the role of the king to show that he is just as interesting as the more established characters. It doesn’t change the fact, though, that the Black Knight is just another story about someone challenging Arthur’s right to be the king – just like in Le Chevalier de la Charrette, Iwein, and Dialogue Between Arthur and Gwenhwyfar.
So, not such a silly cup.