A historical investigation on the shape of armour in the West and in the East. An armour (spelled armor in the US) is a protective covering that is used to prevent damage from being inflicted to an object, individual, or vehicle by weapons or projectiles, usually during combat, or from damage caused by a potentially dangerous environment or action. The word "armour" began to appear in the Middle Ages as a derivative of Old French. It is dated from 1297 as a "mail, defensive covering worn in combat". The word originates from the Old French armure, itself derived from the Latin armatura meaning "arms and/or equipment", with the root armare meaning "arms or gear". Armour has been used throughout recorded history. It has been made from a variety of materials, beginning with rudimentary leather protection and evolving through mail and metal plate into today's modern composites. Significant factors in the development of armour include the economic and technological necessities of its production. For instance, plate armour first appeared in Medieval Europe when water-powered trip hammers made the formation of plates faster and cheaper. Well-known armour types in European history include the lorica hamata, lorica squamata, and the lorica segmentata of the Roman legions, the mail hauberk of the early medieval age, and the full steel plate harness worn by later medieval and renaissance knights, and breast and back plates worn by heavy cavalry in several European countries until the first year of World War I (1914–15). The samurai warriors of feudal Japan utilised many types of armour for hundreds of years up to the 19th century.