For six centuries after the Norman conquest the use of armour was universal. True mail of interlinked rings was generally adopted about the time of the Crusades (1190-94) and its use continued until the fourteenth century; but from about 1300 the practice of protecting the more exposed parts of the body with plates of iron instead of chain mail began to extend, and the character of personal armour gradually changed until it became a complete panoply of plates. The authorities give the period of mixed chain and plate armour as from 1300 to 1410. By the latter date this had disappeared in favour of complete armour of plate, the use of which continued until the beginning of the seventeenth century, growing heavier and stronger in ratio with the increasing efficacy of offensive weapons. We need not follow the decadence of armour through the age when buff coats and jerkins, under “demi-suits of plate,” were in vogue, to its final disappearance far on in the seventeenth century. Our concern lies with those ages during which heavy armour was in use; for this was the long period when the development of the Great Horse was continuously the anxious care of kings and parliaments. The steady increase in the weight of armour is a factor of the first importance in our present investigation; for therein we find the sufficient motive which impelled our ancestors to develop to the utmost the size and strength of the only breed of horse which could carry a man-at-arms. When we find that the weight a horse might be called upon to bear amounted to 4 cwt.--32 stone--at the period when plate armour reached its maximum strength, no further stress need be laid on the power of the animal required. We may find opportunity later on to consider in minuter detail the weight of armour.