The Hundred Years' War 1337–1453

Q&A 6 min read

What Was Plate Armor?

Plate armour was the full-body metal armour that became the standard equipment of the European man-at-arms in the fourteenth and fifteenth centuries. It was made of carefully shaped and articulated metal plates, joined together with leather straps and rivets, and it was the most sophisticated technological achievement of the medieval armourer’s craft. The development of plate armour was, in part, a response to the English longbow and the crossbow; the development of effective gunpowder artillery in the 15th century made it obsolete. The standard treatment is Claude Blair’s European Armour, circa 1066 to circa 1700 (1958) and the more accessible account in Philippe Contamine’s La Guerre de Cent Ans (1968); the contributors to Clifford Rogers’ The Oxford Encyclopedia of Medieval Warfare and Military Technology (2010) give the technical detail.

The development of plate armour

The development of plate armour was a gradual process that took place over several centuries. The earliest form of body armour, used by the ancient Greeks and Romans, was the cuirass, a single piece of metal that covered the torso. The cuirass was supplemented, in the early Middle Ages, by a mail shirt, a garment made of interlocking iron rings that covered the entire body. Mail was the dominant form of body armour from the tenth to the thirteenth centuries.

The transition from mail to plate began in the thirteenth century, with the addition of solid metal plates to vulnerable areas of the mail shirt. The coat of plates, a leather or fabric garment reinforced with metal plates, became common in the early fourteenth century. By the mid-fourteenth century, the full harness of plate armour — a complete covering of articulated metal plates over the entire body — was beginning to appear. The famous Black Prince effigy in Canterbury Cathedral, dating from 1376, shows a complete harness of plate armour that is recognisably modern in form.

The development of plate armour in the fourteenth century was, in part, a response to the longbow. The mail shirt, which had been adequate against the sword and the lance, was inadequate against a longbow arrow at close range. The early plate defences — the coat of plates, the breastplate, the greaves — were the body armour’s response to the longbow. The later development, in the fifteenth century, of the full harness of plate armour was the body armour’s response to the crossbow, the hand-gun, and the early cannon.

The construction of plate armour

A full suit of plate armour, as it was worn in the late fifteenth century, was a sophisticated technological achievement. The armour was made of carefully shaped and articulated metal plates, joined together with leather straps and rivets. The plates were made of iron or steel; the better-quality armour, made for the wealthier customers, was made of hardened steel, sometimes with surface decoration. A typical full suit of plate armour, as worn by a man-at-arms in the Hundred Years’ War, included:

  • a helmet, often a bascinet, which protected the head
  • a gorget, which protected the neck and throat
  • pauldrons, which protected the shoulders
  • rerebraces and vambraces, which protected the arms
  • couters, which protected the elbows
  • a breastplate and backplate, which protected the torso
  • a fauld, which protected the hips
  • cuisses and poleyns, which protected the thighs and knees
  • greaves and sabatons, which protected the lower legs and feet

A full suit of plate armour might weigh as much as 50 to 60 pounds, although the weight was distributed across the body to allow the wearer to move relatively freely. The suit was custom-made, fitted to the individual wearer, and adjusted at the armourer’s workshop. The cost was substantial: a full harness, in the fifteenth century, was worth the price of a substantial horse. The principal centres of armour production in the war period were Milan, Cologne, and the workshops of southern Germany.

The effectiveness of plate armour

Plate armour was remarkably effective against the weapons of the medieval period. A full suit of plate armour could deflect arrows, swords, and early firearms; a man-at-arms in full plate was extremely difficult to kill in single combat. The famous plate armour tests of the nineteenth and twentieth centuries, in which modern longbows and crossbows have been fired at period-accurate plate armour, have confirmed the chroniclers’ accounts. A bodkin-pointed longbow arrow, fired at 30 yards, will penetrate a plate of mild steel, but the plate will stop the arrow; a rounded arrow, fired at the same range, will bounce off.

The armour was also, contrary to popular belief, not as restrictive as is often supposed. A well-fitted suit of plate armour allowed the wearer to move, fight, and even mount a horse with relative ease. The famous accounts of Renaissance fencers wearing full armour are not exaggerations. The limitations of the armour were at the joints — the armpit, the inside of the elbow, the groin — and the helmet visor; a determined attacker who could get inside the plate could still kill the wearer. The chroniclers’ accounts of men being killed through the visor slits, or through the joints, are corroborated by the modern technical literature.

The effectiveness of plate armour was, however, limited by the development of gunpowder. A close-range musket ball, in the 1470s, would penetrate the best plate armour. A close-range cannonball would smash it. The long history of plate armour in European warfare, from the twelfth to the seventeenth century, is bounded on the technological end by the longbow and on the technological end by the musket.

The cost and the social meaning

Plate armour was extremely expensive, and a full suit was a major investment. A man-at-arms who could afford a full suit of plate armour was, by definition, a wealthy man; the cost of armour was a significant factor in the social structure of medieval Europe. The development of plate armour contributed to the increasing expense of medieval warfare, and it was a major factor in the long-term decline of the feudal system. The mounted man-at-arms of the fifteenth century, encased in plate and supported by a retinue of archers, was a more expensive soldier than his thirteenth-century predecessor. The English army that fought at Agincourt in 1415 was a more expensive army than the English army that fought at Courtrai in 1302. The cost of the war, as Anne Curry has emphasised, was one of the structural reasons the war ended where it did.

The decline of plate armour

Plate armour declined in importance during the late fifteenth and early sixteenth centuries, as the development of effective gunpowder weapons made the full suit obsolete. The armour was gradually reduced in coverage, and the breastplate, which could still provide some protection against early firearms, was the last major piece of armour to be worn by European soldiers. The full harness of plate armour had, by 1600, disappeared from European warfare; the half-armour of the seventeenth century was a ceremonial or cavalryman’s armour, not a battlefield armour.

Significance

The development of plate armour was one of the most important technological achievements of the Middle Ages. The armour, which was a sophisticated combination of metallurgy, engineering, and craftsmanship, had a profound effect on the conduct of medieval warfare, and it was a major factor in the social structure of medieval Europe. The history of plate armour, in the standard reading of Contamine, is the history of the long medieval period in which the mounted man-at-arms was the decisive battlefield arm. The period ended at Castillon in 1453, in a different sense than is often realised: not only did the English army lose, but the mounted man-at-arms as a tactical category lost with it. The full plate harness, which had defined the mounted warrior since the thirteenth century, was already on the way out by the time of the war’s end.