It’s also worth noting the term is “capture”. And outside of rare instance - you didn’t really want to kill knights and the like: You captured them, and ransomed them back to their family/liege lord etc.

And there is a reason the term “Kings Ransom” exists. John the II of France for instance was captured, and Ransomed for something like 300000 gold coins of the day - something like 300 million or up to about 3 billion in today’s dollars (conversion is a little fuzzy but to put it simply: A BLOODY TONNE OF MONEY).