Full plate armour peaked after the Middle Ages, not during them
The shining knight in full plate is usually pictured in the medieval era, yet complete suits only appeared around 1420 and reached their peak in the 15th and 16th centuries. Much of that popular image comes from specialised jousting armour of the 1500s, the Renaissance rather than the age of castles.
Before plate came mail, hundreds of small interlinked iron or steel rings, sometimes riveted, that followed the body's contours and resisted cuts and thrusts better than blows from clubs. From the 10th to the 13th centuries it dominated so thoroughly that the period is called the age of mail. From the late 13th century, single plates were added over mail to guard joints and shins, and the coat of plates marked the transitional armour of the 14th century, especially during the Hundred Years' War.
By about 1420 a full European suit ran from helmet and gorget through pauldrons, vambraces, gauntlets, breastplate and backplate down to greaves and sabatons. Armourers learned to articulate overlapping lames for flexible joints and to fit suits like tailors. Bespoke armour cost a fortune, so most soldiers wore cheaper munition pieces, the equivalent of ready-to-wear, and the grandest sets, called garnitures, had interchangeable parts for fighting on foot or horseback. Swiss mercenaries and Landsknechts favoured lighter three-quarter suits that left the lower legs bare.
Plate had ancient roots. The bronze Dendra panoply of late Bronze Age Greece protected the whole torso, and Rome used the segmented lorica segmentata from the 1st century BC to the 4th century AD. In Japan, iron cuirasses called tankō were made in the Kofun period. After the Portuguese introduced matchlocks in 1543, Japanese makers produced tōsei gusoku armour of large iron plates, including bullet-tested tameshi gusoku, and samurai armour last saw use in the Satsuma rebellion of 1877.
In Europe plate declined in the early 17th century as weight hindered mobility and muskets could pierce common armour at range, though monarchs such as Gustavus Adolphus still wore it and Polish Hussars kept substantial plate. It shrank to the cavalry cuirass, regained value for infantry against shrapnel late in the Napoleonic Wars, and returned as steel plates in World War II flak jackets before fibre-reinforced plastics replaced them.
Source: Plate armour
