<P> Armour did not always cover all of the body; sometimes no more than a helmet and leg plates were worn . The rest of the body was generally protected by means of a large shield . Examples of armies equipping their troops in this fashion were the Aztecs (13th to 15th century CE). </P> <P> In East Asia many types of armour were commonly used at different times by various cultures including, scale armour, lamellar armour, laminar armour, plated mail, mail, plate armour and brigandine . Around the dynastic Tang, Song, and early Ming Period, cuirasses and plates (mingguangjia) were also used, with more elaborate versions for officers in war . The Chinese, during that time used partial plates for "important" body parts instead of covering their whole body since too much plate armour hinders their martial arts movement . The other body parts were covered in cloth, leather, lamellar, or Mountain pattern . In pre-Qin dynasty times, leather armour was made out of various animals, with more exotic ones such as the rhinoceros . </P> <P> Mail, sometimes called "chainmail", made of interlocking iron rings is believed to have first appeared some time after 300 BC . Its invention is credited to the Celts, the Romans were thought to have adopted their design . </P> <P> Gradually, small additional plates or discs of iron were added to the mail to protect vulnerable areas . Hardened leather and splinted construction were used for arm and leg pieces . The coat of plates was developed, an armour made of large plates sewn inside a textile or leather coat . </P>

What new inventions during the time period of knights made the knights armour obsolete