Primary Sources: Le Morte D’Arthur, Book III Chapter XV
When Pellinore and Nimue get to Camelot, Arthur is out jousting, but Merlin and Guenever are there. Merlin casts zone of truth again, and Pellinore lays out the whole story, culminating in his retrieval of the damosel’s head at Nimue’s suggestion.
“So this damosel died because he couldn’t be bothered to stop and he ignored her requests for aid…” Guenever shakes her head. “Is he leaving anything out?” Guenever asks Nimue.
“Not that I know of, ma’am. The parts I was there for, I can confirm,” she says. “I mean, I did spend a lot of this story tied up in a tent.”
“Great. Just great,” says Guenever. “All right. Ladies!” She snaps her fingers and a host of ladies-in-waiting appear…
“Hold on!” interrupts Merlin. “I’ll handle this one!”
Guenever shrugs. “As you were, ladies, apparently Merlin is going to actually do something today,” she says.
“It’s your fault anyway,” Pellinore tells Guenever.
“Really? My fault? How do you figure that exactly?” Guenever straightens up.
“It was your wedding,” says Pellinore. “That Nimue disrupted with her hounds —“
“Am I going to get my white brachet back, by the way?” Nimue asks. No one answers her.
“Go on,” says Guenever. She is looking daggers at Pellinore. “My wedding, you said.”
“So clearly it’s your fault,” says Pellinore.
Guenever turns to Merlin. “This guy is in the Round Table on your say-so, right?”
“It’s for the best,” says Merlin.
“That line may work on Arthur, Merle, but I’m a big girl —“
“It is for the best! It’s got to be this way, Guenever. Ma’am. I’m not just saying this because I’m half demon.”
Guenever looks skeptical, but lets it go.
“Now, Pellinore,” Merlin says, turning back to him. “Truly you are a foul jackass and you should feel bad.”
“I do feel bad!” says Pellinore. “I’ll feel bad about it for the rest of my life! I’m just saying Guenever should feel worse.”
“Shut up, man, I’m trying to help you not get thrown off the Round Table here,” hisses Merlin. Then, louder, he continues. “You should feel bad, Pellinore! Feel bad! And know that this poor damosel whose head you hold is your own daughter! Yes, Eleine, daughter of the Lady of the Rule!”
“Oh, the Lady of Rule, man, the affair I had with her… oh, wait, jeez, this is another illegitimate child I didn’t know about?”
“Eleine, who was traveling here with her beau Sir Miles of the Launds, and a tearful reunion it would have been, were it not for her sad fate!” Merlin cries. “A foul villain, Loraine the Thug, false knight, coward, snuck up behind Sir Miles of the Launds and stabbed him with a spear! And she slew herself out of sorrow at his passing! And because she’s now dead, you shall one day be in great trouble and your best friend will abandon you just when you need him most! This will happen! Carry this doom forward! The man you trust most shall betray you and lead you into peril and abandon you to die!”
“Well, crap,” says Pellinore.
“Hmm, I’ll allow it,” says Guenever.
Then Arthur comes back from the jousting, and Guenever fills him in on the situation and gives him some lines for a speech she want him to make. And once all the strange adventures are finally over, he gathers all his knights together and makes said speech. It’s about how murders, atrocities, random acts of cruelty, and treason are all forbidden them for so long as they’re in his court, and about how they must always give mercy when it is asked for, upon pain of being exiled from Camelot, and to always help out women, damosels, gentlewomen, and ladies in need on pain of getting hunted down and slaughtered like animals, Arthur is not kidding about that. PS, he says, no fighting for unjust causes regardless of how much money they offer you.
All the knights swear to abide by this oath which sounds suspiciously like an Advanced Dungeons & Dragons paladin’s code of conduct, and we close out the third book. Next: Book IV, which is where we dispense with these preliminaries and get into full-on flower-of-chivalry nonsense!
So I guess not ignoring damosels in distress and not committing murder, treason, random acts of cruelty (I presume premeditated/non-random acts of cruelty are ok at this point?) and other atrocities is just the budding of the flower of chivalry?
Clearly, chivalry is developed through an exhaustive method of trial-and-error.