One of Richard III's wounds is a blow that penetrated his pelvic bone after he was stabbed in the right buttock. This has been interpreted as a wound inflicted after death to humiliate him.
But I believe it could well have been struck in combat. An attacker can defeat plate harness worn with a mail skirt by moving in close and stabbing upwards with a dagger from below. This is entirely consistent with the wound on Richard's pelvis. This is easiest when the victim, like Richard, faced several assailants. Then an attacker could easily move close enough to strike a low blow upwards from behind. But it was effective enough that even a single attacker might attempt it as in this 1403 encounter at Valencia recorded by Monstrelet:
"Then Sir Jacqes de Montenay threw down his axe, and with one hand seized Sir Pere de Moncada by the lower edge of his lames. In the other he had a dagger with which he sought to wound him underneath."