Although the majority of historical chain maille is armor, maille jewelry techniques were also used by cultures as diverse as the Celts, the Vikings, and the Egyptians.
The oldest piece of maille armor to be accurately dated is more than 2,700 years old, discovered in the graves of Celtic warriors. The name comes from the French word "maille" which is derived from the Latin "macula" meaning "mesh of a net". Other evidence of chain maille has been found in graves in Scythia from the 5th century.
When worn as armor, maille has the ability to expand and contract which means it can accommodate breath and movement. This could lend a warrior an important advantage over others who wore more constricting clothing, such as solid suits of armor. For more info and many examples of chain maille, visit this article on WIKIPEDIA