Jack Chains were an important part of the protective equipment of the medieval foot soldier who, typically, was not dressed in plate armor but wore a padded arming jacket (“jack”) to protect his upper body. This was quite effective in protecting the torso but left the arms vulnerable to slashing sword cuts. This led to the development of “Jack Chains”, which were simply multi-jointed steel strips sewn to the outside of the sleeves of the jacket, from the shoulder to the wrist, and which often incorporated a dished plate to cover the outside of the elbow. Modern studies have indicated that these chains prevented up to 80% of potential arm injuries