Chivalry is designed; it isn't a naturally ocurring ethos. The chivalrous tradition (in its original and ideal form) is not a compromise between gentleness and ferocity, but is the apotheosis of both, simultaneously. Practically, a person who is only tame and incapable of inflicting harm is doomed to be a coward. Likewise, someone who is brutal and refuses to be meek, a barbarian.
The man who combines both characters—the knight—is a work not of nature but of art; of that art which has human beings, instead of canvas or marble, for its medium.