Since ancient times, soldiers have worn special clothing or armor to protect themselves during warfare. Hard materials like leather, wood, shells, and even woven reeds were used to give soldiers extra protection against enemy arrows. Metal started to be used for armor about 3,500 years ago, by warriors in the Middle East. By the time of the ancient Greeks, about 1,000 years later, soldiers were well protected, wearing large pieces of metal on their chests and backs, shin guards, and metal helmets, and they carried metal shields. Soon armored clothing, garments with metal strips and plates attached, began to be made for soldiers. Then chain mail, a type of metal cloth, was developed. Made of small metal rings linked together, chain mail was much more flexible than metal plates, but could not withstand the force of larger weapons, like lances. So full suits of armor made of steel plates, hinged at the knees and the elbows, came into use around the fourteenth century. Soldiers were covered with steel from head to toe, with heavy metal helmets covering their faces, heads, and necks. A warrior could see and breathe through small slits or openings in the helmet’s visor, a movable metal flap that could be lifted up. (Only important or wealthy warriors could afford this kind of elaborate armor.) Suits of armor weighed so much that the soldiers or knights who wore them usually could not move around in them very well; they wore such armor mostly when they fought on horseback. Even the horses sometimes wore armor. As the methods and weapons of warfare changed, clumsy personal armor was no longer useful. It became far more important for soldiers to be able to move quickly and easily. Today’s soldiers usually wear cloth uniforms, body armor, and steel helmets. But armor is used on war vehicles like tanks, naval vessels, and aircraft. The bulletproof vests that police officers use are also a type of armor.