Illustrator Alan Lee served as the film's conceptual designer. Despite heavy fantasy elements, the production is historically accurate to a degree, in keeping with the probable origins of the Arthurian legend in Sub-Roman Britain. The costumes and props used in the film include Dark Age or Early Medieval Celtic and Roman-style weapons (e.g. Iron Age swords) and armor (e.g. mail, scale and leather), while other Arthurian films like "Excalibur", "Knights of the Round Table" and "First Knight" use High Medieval or Late Medieval-style weapons (e.g. longswords) and armour (e.g. full suits of plate). However, some anachronisms are present, like the use of the terms "knight" and "Sir" and the presence of the Roman "lorica segmentata" armour years after it was discontinued. During the conflict between Vortigern and Uther, Uther is said to be invading from Normandy, despite the film taking place long before the age of the Vikings, and thus of the Norman colonization which gave Normandy its name.