It was sometimes more expensive than plate armour. Spaulders are pieces of armour in a harness of plate armour. It could be made from any combination of leather, mail, or plate armour. Usually worn over or under leather, mail, and later plate armour. In Russia there are three known varieties of mail and plate armour. The Persians used mail armour as well as mail and plate armour. They represented the last gasp of full plate armour on the battlefield. Historically a piece of plate armour covering the torso. The armoury preserves a collection of historical plate armour (cuirasses or half-armour). In the eastern zone, warriors are frequently buried with helmet and a plate armour breastplate. The combatants took the field in the early afternoon, mounted and dressed in plate armour. Plate armour was virtually invulnerable to sword slashes. The evolution of plate armour also triggered developments in the design of offensive weapons. By about 1420, complete suits of plate armour had been developed in Europe. It was well suited to penetrate plate armour and chain mail.