Plate armour, which protected the chest and the lower limbs, was used by the ancient Greeks and Romans, but it fell into disuse after the collapse of the Roman Empire because of the cost and work involved in producing a lorica segmentata or comparable plate armour. Single plates of metal armour were again used from the late 13th century on, to protect joints and shins, and these were worn over a mail hauberk. By the end of the 14th century, larger and complete full plates of armour had been developed. During the early 16th century the helmet and neckguard design was reformed to produce the so-called Nürnberg armour, many of them masterpieces of workmanship and design.  European leaders in armouring techniques were northern Italians and southern Germans. This led to the styles of Milanese from Milan, and Gothic from the Holy Roman Empire. England produced armour in Greenwich and they both developed their own unique style. Maximilian style armour immediately followed this, in the early 16th century. Maximilian armour was typically denoted by fluting and decorative etching, as opposed to the plainer finish on 15th-century white armour. This era also saw the use of closed helms, as opposed to the 15th-century-style sallets and barbutes. In Japan elite Samurai wore armour made of tightly sewn plates which had many of the properties of solid plate armour. With the arrival of Europeans the Japanese would add solid plates to their designs. Turkey also made wide use of plate armour but incorporated large amounts of mail into their armour, which was widely used by shock troops such as the Janissary Corps. In the rest of the world, though, the general trend was towards mail, scale, or lamellar armour.
Full plate armour was expensive to produce and remained therefore restricted to the upper strata of society; lavishly decorated suits of armour remained the fashion with 18th-century nobles and generals long after they had ceased to be militarily useful on the battlefield due to the advent of inexpensive muskets. Reduced plate armour, typically consisting of a breastplate, a burgonet, morion or cabasset and gauntlets, however, also became popular among 16th-century mercenaries and there are many references to so-called munition armour being ordered for infantrymen at a fraction of the cost of full plate armour. This mass-produced armour was often heavier and made of lower quality metal than knight armour. From the 15th century on, armour specifically designed for jousting (rather than for battle) and parade armour also became popular. Many of the latter were decorated with biblical or mythological motifs.
Armour was not confined to the Middle Ages, and in fact was widely used by most armies until the end of the 17th century for both foot and mounted troops. It was only the development of powerful rifled firearms which made all but the finest and heaviest armour obsolete. The increasing power and availability of firearms and the nature of large, state-supported infantry led to more portions of plate armour being cast off in favour of cheaper, more mobile troops. Leg protection was the first part to go, replaced by tall leather boots. By the early part of the 18th century, only field marshals, commanders and royalty remained in full armour on the battlefield as they were tempting targets for musket fire. However, cavalry units, especially cuirassiers, continued to use front and back plates that could protect them from distanced fire and either helmets or "secrets", a steel protection they wore under a floppy hat. Other armour was hidden under decorative uniforms. Body armour made a brief reappearance in the American Civil War with mixed success. However, the armour vests of the time were expensive and thus bought by individual troops and not issued, meaning that the effectiveness of the armour varied widely depending on its maker. Plate armour was successfully implemented by Australian outlaw Ned Kelly and his gang, giving them a large advantage in their gunfights against police. The cavalry armour of Napoleon, and the French, German, and British empires (heavy cavalry known as cuirassiers) were actively used through the 19th century right up to the first year of World War I, when French cuirassiers went to meet the enemy in armour outside of Paris. During the war both sides experimented with shrapnel armour and some soldiers used their own but dedicated ballistic armour such as the American Brewster Body Shield was not widely produced.
Plate armour briefly re-appeared during World War II on some Soviet Guard (elite) infantry units, who wore steel breastplates that could stop rounds fired by pistols and submachine guns. The Japanese and Americans made several prototypes but none were mass-produced due to their cost and the need for metal elsewhere. In the Korean War, body armour was re-introduced for U.S. foot soldiers, and then to a greater extent in the Vietnam War. Modern U.S. soldiers in Iraq now always wear light-weight Kevlar helmets and armour vests, the latter often augmented with more-or-less rigid ceramic plate inserts. The U.S. Air Force used flak jackets as a form of plate armour. The 1970s introduction of aramid (Kevlar or Twaron) body armour brought sheet metal (especially titanium) trauma plates back into fashion as a form of rifle-grade add-on to flexible vests, and ballistic metals are gradually improving with stronger and lighter alloys being steadily developed. Lighter ceramic plates are still the choice of most first-world militaries, but titanium and ballistic steel are still in wide use by those wanting a less costly option.