Around 1200 AD across the Holy Roman Empire and Western Europe, knights began deploying the Great Helm (heaume). This massive, cylindrical iron helmet completely enclosed the warrior's head, resting on the shoulders and providing only narrow horizontal slits for vision and small ventilation holes. This total facial enclosure offered unmatched protection against lance impacts during tournaments and charges, but severely restricted breathing and peripheral awareness.

The psychological effect of the Great Helm transformed European literature by completely hiding a knight's face and expressions on the battlefield. This sensory isolation birthed the classic literary trope of the anonymous or 'unknown knight' in Arthurian romances, a device used by poets to create dramatic tension and thematic mystery.