Chain mail was a form of metal "cloth" made by hooking small, round, metal links together. Iron workers formed long, thin strips of metal that are then cut into shorter lengths that could be forned into the links. These were then knitted together as one would string paperclips together and arranged into the shape of the desired garment. Chain mail was relatively light, very flexible and, of course, "breathed" (let the sweat and body heat out). Introduced in ancient times, for over a thousand years chain mail served principally to make hauberks (a long sleeve, knee length shirt weighing 20-30 pounds.) After 1000 AD, chain mail hoods and leggings became popular, adding another 10-15 pounds of weight. Chain mail was always worn over heavy wool clothing that served to cushion blows, while the chain mail prevented swords and axes from penetrating. In the mid 14th century.chain mail was gradually replaced by plate mail .