When you take part in hand-to-hand combat you need protection from the blows of your opponent. When your opponent carries a sword, axe or lance, no fabric can be thick enough to protect you. Boiled leather was worn by the foot soldiers, but this protection was limited against a sharp blade.
Because of my interest in things medieval, I’m always on the lookout for second hand books on the subject. I’ve got an amazing book called Knights by Andrea Hopkins. One of the features in the book is some coloured plates of armour through the ages, which I want to share.
The earliest form of mail was plates or scales sewn onto a backing fabric. Examples have been found from thousands of years ago. The best known today is probably the samurai armour of Japan. 
Chain mail is made from thousands of tiny metal links which resist cutting edges. It moves like fabric, so allows the wearer some freedom of movement. Blows can, however, drive the links into the skin underneath, so it is necessary to wear some form of padding underneath.
French Cavalryman c.900 
This Carolingian warrior wears a chain mail hauberk which is slit at the sides. This suggests that he is accustomed to fighting on foot as well as on horseback. He wears a simple conical helmet which, however, is decorated. His lance has lugs beneath the blade, which indicate a thrust and parry style of fighting. Although his horse has a framed saddle and stirrups, the technique of charging with couched lance is still 150 years or so in the future. He carries a round shield with a spiked boss in the centre which could also be used as a weapon, and on his feet he wears leather shoes with a simple prick spur. His sword is of the early type with a rounded end to the blade, designed for cutting rather than stabbing.
Knight in Quest of Adventure c.1180 
This knight carries a lance which he may couch to charge his opponents, but since it is not decorated with a pennon or banner he could also throw it, a technique equally favoured at this date. His helmet, with round top and nasal bar, is of a style introduced around 1100. His mail hauberk or byrnie has been extended; it now incorporates a hood or coif; a loose flap (aventail) hanging in front of his throat can be pulled up and secured by thongs to helmet or brow to protect his face, and the sleeves are now lengthened into mittens. He carries the characteristic kite-shaped Norman shield and rides in a saddle with a raised pommel and cantle (behind) to give him an extra secure seat during combat. His shins are protected by mail greaves.
A Templar and a Hospitaller c.1250 
The Templar (on the left) is wearing a padded arming cap, on which his helm will rest. His mail hauberk is now worn over a padded undercoat called a gambeson, and under the surcoat of the Order – white, with a red cross on the breast. The loose, knee-length garment is split to the waist at front and back for ease when riding. He has mail leggings and prick spurs.
The Hospitaller wears the black surcoat with white cross which was adopted by the Order in 1248; in 1259 this was changed to a red surcoat with a white cross. He wears a simple round helmet over his mail coif. Shields have by this time grown shorter and more triangular in shape. The mail leggings are laced behind the knight’s calves.
Modern Day
Chain mail is still in use today, in two particular places: divers wear mail suits as protection against sharks, and butchers wear mail gloves when they are butchering meat.