Plate armour is a historical type of personal body armour made from iron or steel plates, culminating in the iconic suit of armour entirely encasing the wearer. While there are early predecessors such as the Roman-era lorica segmentata, full plate armour developed in Europe during the Late Middle Ages, especially in the context of the Hundred Years' War, from the coat of plates worn over mail suits during the 13th century.

In Europe, plate armour reached its peak in the late 15th and early 16th centuries. The full suit of armour is thus a feature of the very end of the Middle Ages and of the Renaissance period. Its popular association with the "medieval knight" is due to the specialised jousting armour which developed in the 16th century.

Full suits of Gothic plate armour were worn on the battlefields of the Burgundian and Italian Wars. The most heavily armoured troops of the period were heavy cavalry such as the gendarmes and early cuirassiers, but the infantry troops of the Swiss mercenaries and the landsknechts also took to wearing lighter suits of "three quarters" munition armour, leaving the lower legs unprotected.