I am developing a world were modern firearms are introduced into a medieval setting (I realize that this has been done since Mark Twain's *A Connecticut Yankee in King Arthur's Court*). I'm working on how my world will react to the introduction of such weapons.

**Given:**

* 14th Century Europe (if a specific location is required, use France).
* A knight wearing common plate mail of the time.
* An M1911 pistol using a .45 ACP round.

**Question:**

What 14th century technology could be used to protect the knight from the M1911 pistol while leaving the knight able to walk, fight, and ride a horse?