“What should we do with him? Throw him in a pit?”

“Are you mad? This is the king of France we’re talking about!”

“So?”

“So you can certainly assassinate such a royal body in his sleep—God forbid!—but once you catch him on the battlefield, you’re expected to ice the cake, put a cherry on top and cut him the better slice.”

“You mean I should provide him with clean sheets, refined meals, proper wine and everything?”

“Obviously! Also, you should be the one to wait on him at dinner.”

“Are you kidding? I just won the battle against him! I covered him in ridicule.”

“So? You’re a prince, he’s a king. Do the math!”

“This will cost me an arm and a leg...”

“Now you understand. You should have let him slip away.”

"But... the glory."

"Halas! The glory."

---------------------

It seems there's sort of an unwritten code among the elite to treat each other with dignity.

Indeed, there was such a code. As a matter of fact it was even written down.

War was a violent thing that stood against everything Christianity was supposed to uphold. For centuries clerics were at odds with the aristocracy regarding what could or couldn't be done on the battlefield, especially once Catholicism triumphed from all the other shapes of Christianity in Western Europe such as Arianism. It was fine and dandy to battle off Arians or to butcher Pagans (the Teutonic Order did it until very late in the Middle Ages) to insure the Catholic supremacy over the West but what about going to war with your fellow Catholic lord over a land dispute? How could that ever be allowed?

Theologians ended up thinking war as a natural state of mankind, something that couldn't be avoided because "boys will be boys" after all (something the last decades of European history have proved to be a false assumption: peace can be achieved through education). Therefore violence was to be filtered and moderated. That’s how the code of chivalry came into being—a code that wasn’t universally shared which explains why French knights seem to behave so foolishly when they’re abroad or faced with adversaries who don’t share their cultural background.

In the 14th century, Honorat Bouvet wrote L’Arbre des batailles (the Tree of Battles) which summed up most of what could or couldn’t be done on the battlefield. Many medieval intellectuals actually wrote on the proper and expected behavior of knights and gentlemen in and out of the battlefield but Bouvet’s masterpiece is really the one that struck. It counts among the earliest book to be printed to give an idea of its cultural importance at the time—back when printing a book was actually a grand affair.

I’ve written several time about ransomed knights on this subreddit and I invite you to read my previous contributions on the matter (click on the links in this paragraph). Bertrand du Guesclin and Arthur de Richemont, who both became the highest ranking officer of the French army, were captured during their early military career and it costed them dearly. However, they were granted the right to move around the country to deal with their various business. Bertrand du Guesclin was freed to collect the money of his ransom. Arthur de Richemont received the right to meet his brother and many Briton lord who’d have broken him free if only he’d asked for it but the code of chivalry prevailed.

I imagine it's also rare for a leader to be captured.

It was certainly more common than what modern warfare would allow. Generals, high ranking officers, kings, etc. were expected to be on the first line of their army. Remember that the French could look like fools abroad? French knights had a very strict code of conduct: they had to be the first on contact with the enemy and they couldn’t retreat for the life of them. Alain Chartier wrote a pleasant piece of literature where several women argue about their misery. Which of them is the most to pity? The first has lost her husband: he died on the battlefield. The second one doesn’t know where her husband is, he’s missing in action. The third, however, is the saddest of all. Her husband is alive but he fled the battlefield! That kind of shame is insufferable. As I’ve written previously about tournaments:

As in regard of shame, there were little to none if you “lost” in a jousting event or in a tournament. The only one and true shame would have been to refuse to participate unless you were already at war or on a crusade.

The same rule applied to warfare—for jousts and tournaments were merely an extension of actual warfare until the 16th century. Therefore you were expected to show up on the battlefield and not to retreat at any cost. Anything less could bring you much trouble and headaches since everybody was held to that high standard. In those conditions, it is not so difficult to surround and capture the enemy military leader. Even upon retreat they’re expected to guard the rear of their troops. Philippe VI of France was dragged out of Crécy (1346) by force when his officers reckoned the battle was lost. A few horses had died under him and an arrow hit his head during the battle.

Talking about French kings and the Hundred Years War, the most impressive capture of all was when John of France was captured by the Black Prince at Poitiers (1356). Here’s the story as I’ve written it on my blog:

The battle of Poitiers (1356) saw the Black Prince and his 6,000 men (3,000 men-at-arms, 2,000 archers and 1,000 mounted infantry) oppose a French army 10,000 men strong, led by King John II himself, his heir, who would later become Charles V of France, and the full force of the royal army: the Constable and both Marshals were there.

The French army charged the Black Prince’s troops on three occasions. Each wave was defeated when a fourth almost brought Edward of Woodstock to his knees. His men were exhausted from the battle, his archers almost out of arrows and, this time, King John himself was leading the charge with his elite reserve and many rallied soldiers. In a desperate counterattack, the Black Prince moved forward and pushed towards the French, leaving his defensive position. He sent the Captal de Buch to circle around toward the French rear with 160 mounted men, hoping to break the French’s formation. He won his risky gamble. The French were routed out of the battlefield and King John was captured!

The same night, Edward of Woodstock waited on King John’s table himself. Sensing there might be tension, he kneeled in front of the king and handed him his rosary. He told King John his father, Edward III of England, would treat him right and be his friend, for they had much in common. This show of humility moved the many ransomed French knights who witnessed the scene and it gave much credit to the Black Prince.

Captured military leaders were therefore well treated. The high nobility “belonged to the international community of the wealthy” as I’ve written before. They respected a set of rules that separated them from the common people. This is also why they couldn’t wage war and regular people couldn’t. You could win one battle but lose another. You could be captured once but capture your enemy another day. In this context aristocrats expected to be extended some curtesy. It is quite rare, in fact, that someone couldn’t be liberated at any cost or would be imprisoned in a secretly held location. It did happen but even those people were treated decently for they belonged to the “better half” of society or the “top 1%” as we’d say today. Only if you were deemed as an outright traitor or a man of no principle would you be treated harshly. It did happen, certainly, but less and less as the code of chivalry tightened its grip on the aristocracy.