The first shields were made of leather, woven reeds or wicker.
There were designed to stop arrows fired from bows and did that well.
But melee attacks with hand weapons apply a lot more force and can whack such a shield to pieces quite quickly.
Therefore heavy infantry started to use sturdier wooden shields.
When metal working was invented, many shields were reinforced with metal at the edges and in the center with a boss.
In theory smiths can make stronger full metal shields, but these are so heavy that they are very impractical.
Sometimes wooden shields were covered by a thin sheet of metal, to get some additional sturdiness without increasing the weight too much.
The reinforced wooden shield remained in use for millennia.
Shields come in many different sizes.
The smallest bucklers, used in Renaissance duels, were no more than 0.15 meters in diameter.
On the other end of the size range are body shields, up to 1.2 meters tall and half as wide.
Italian crossbowmen used even larger shields.
They operated in teams of two men, one of them holding a pavise shield that was so big that it could protect both men
while the other reloaded his crossbow.
Cavalry shields tended to be smaller than infantry shields because the body of the horse gets in the way of large shields.
The shape of shields has also varied throughout the ages.
The Mycanaeans used a 8-shaped shield, while the Greek hoplite "hoplon" aspis was simply circular.
Some shields had a basic simple geometrical from, with an 'eyehole' cut out at the top.
The Romans used a large oval scutum, which later became rectangular and later still oval once more.
Vikings again used round shields, the Normans triangular kite-shaped ones.
When plate armor was developed, armor became so good that the need for a shield waned.
Shields first became smaller, like the Medieval heater shield, then mostly disappeared.
Throughout history the large flat surfaces of shields have been used not only for defense, but also to put emblems on them.
In the European Middle Ages heraldry, knowledge of the meaning of all colors and symbols, became so complex that only specialized heralds knew all of them.
War Matrix - Shield
Prehistory 35000 BCE - 3500 BCE, Weapons and technology