Metallurgical examination of three swords shows differences in techniques employed to produce a hard cutting edge without excessive brittleness: a late Iron Age sword from Waltham Abbey, England, has a composite, partially carburized structure; a 9th/ 10th century sword from Lincoln, England, was made by slack-quenching a composite structure; a 15th/ 16th century sword from Solingen, Germany, by quenching a selectively carburized structure.