Chivalry was pretty much an invention of the ruling oligarchy in the late dark ages, when life, government, and hope were pretty brutal and pretty nasty.
Feudalism was a nasty ruling means, and its wars were fought for pretty nasty reasons. Most soldiers in most wars then depended on pillage, rape, theft, chicanery and terror as a way of life. If you went to war, you got to kill people and steal their shit. There wasn't any bright side to it, no Camelot, no light, no wonderful people. It sucked. Chivalry was an invention intended to place the peers, the Knights, the aristocracy in a special place, by inventing special behavior that they were supposed to engage in. In real life in medieval times, it didn't exist. There was no real Camelot, the tales were around a cast of English royalty ( understand that royalty then meant "Kings" with 100 followers and Knights with four), that didn't exist in real life. Arthur, Uther/Luther, Gwenivier ( many spellings) and all of other myths were just that.
In reality, English and Continental fuedalism consisted of hundreds of years and many generations of war where "royal" families fought other royal families to obtain and advantage, power, prestige, and wealth. The slaughters were epic, the deeds of darkness incredible ( imagine being drawn and quartered after you were flayed alive and your intestines were removed and you were hung from them), and the lives short.
Chivalry never existed. It was part of a myth that the ruling class invented to hold onto power.