I have not read the original sources, and the information I gleaned is from the Osprey "Battle of Bosworth Field, 1485", but this situation just raises some questions for me.

At the battle of Bosworth Field and ultimate demise of Richard III, the king's standard bearer, Sir Percival Thirlwall, supposedly held the king's standard high even after having both legs cut off, before, obviously, succumbing to his wounds.

Things to consider: As a standard bearer and being of the king's household, Thrilwall would have been wearing some of the finest plate armour of the time. Also, as standard bearer you are to protect the banner at all costs and not to let it fall to the ground.

Questions: Is it possible for him to have both legs severed during combat wearing full plated legs? If he weren't immobilized by a prior injury and was able to move normally, is it possible, even for a halberd, to sever his legs? archeological evidence at Wisby shows it is possible to have both legs severed by one blow, but while wearing up to the date plate?

Possibilities: Maybe he was all ready injured and on the ground. Maybe it was done after the battle, as Richard III was mutilated after his death by his enemies. Maybe he had always had prosthetics and in the heat of the battle they somehow became unattached. Maybe he was the Black Knight, "I'm invincible!!!"

It's also possible that he wasn't wearing leg armor at the time. A man-at-arms was certainly supposed to possess leg armor, but it seems that in some circumstances he was allowed to take at least some of it off. What battle was it, I wonder, where the men-at-arms discarded their "cuissards" for better mobility on foot?