This thesis is an interdisciplinary study of medieval armour, with the goal of determining the precise techniques used by medieval armourers in the practice of their craft. The corpus for this research is from the collection of the Royal Armouries, as well as a selection of objects from other museums, with a focus on German and Italian armour between 1400 and 1500. The thesis makes use of a new methodology by which the armour itself is used as a primary source, in essence a text, using the interpretation of tool marks left on its surfaces. Although metallurgical studies have been undertaken on armour, the marks have not been systematically studied in the past and provide a means by which the techniques of the medieval armourer may be ...