Just found this short film and highly recommend it:

This one really shows just how formidable a knight in armor could be. He’s not invincible by a long shot, but you’ve got basically a football player who has practiced close-quarters combat for his whole life covered in two layers of steel; there really aren’t a lot of good options for dealing with that. There’s a reason they remain in our cultural memory as an archetype of the indomitable hero.