The industrialisation and mechanisation of war in the early twentieth century, including increased use of artillery, tanks, and machine guns and the advent of trench warfare, resulted in an unprecedented number of killed and wounded right from the outset of World War I in 1914. The large number of head wounds suffered by combatants soon made it apparent that metal helmets, although long out of use, were absolutely necessary on the modern battlefield, and that other forms of armor also should be explored.
