The fourteenth century saw a transformation of the coat of mail into a suit of armour of polished steel, which, with some variations, caused by the introduction of portable fire-arms, remained the ordinary armour of the man of war until the time of its final disappearance. Towards 1325 the transformation was complete, as is proved by a great number of monuments of the time, including sculptured figures on tombs, paintings, manuscripts, sepulchral figures engraved on plates of copper, &c. These monuments and documents show that the military costume and equipment of the fourteenth century varied more than is generally imagined. Every man of war armed himself as he thought fit; but there are enough records to give an idea of the type that prevailed and even to guide the archæologist as to the dates of particular changes. What caused the ancient coat of mail to be given up was its weight, and at the same time its incompleteness for defensive purposes. It could stop the thrust of a sword and even of a lance, but in collision the effect of the shock was felt; and in adopting leather jerkins, and afterwards steel plates, the object was to spread the effect of the shock over a greater surface. The coat of mail was not abandoned, but it was worn shorter and of lighter make, without its former accessories, and thus greater lightness and greater facilities of movement were gained. The warrior towards the end of the thirteenth century was oppressed by his equipment, and did not get off his horse. After the transformation he was able to fight on foot, as he did in all the celebrated battles of the fourteenth century, beginning from Crécy (1346). After the adoption of steel armour the coat of mail was still for a time worn underneath; but as the steel armour became more solid the coat of mail was gradually abandoned. The museum contains the complete armour of a man and horse, which dates from the middle of the fifteenth century.