As a subject for careful study and exhaustive investigation perhaps no detail of human existence can be examined with quite the same completeness as can the defensive armour and weapons of past ages. Most departments of Literature, Science, and Art are still living realities; each is still developing and is subject to evolution as occasion demands; and for this reason our knowledge of these subjects cannot be final, and our researches can only be brought, so to speak, up to date. The Defensive Armour of Europe, however, has its definite limitations so surely set that we can surround our investigations with permanent boundaries, which, as far as human mind can judge, will never be enlarged. We can look at our subject as a whole and can see its whole length and breadth spread out before us. In other aspects of life we can only limit our studies from day to day as invention or discovery push farther their conquering march; but, in dealing with the armour of our ancestors, we know that although we may still indulge in theories as to ancient forms and usages, we have very definitely before us in the primitive beginnings, the gradual development, the perfection, and the decadence or passing away, an absolutely unique progression and evolution which we can find in no other condition of life. The survival of the fittest held good of defensive armour until that very fitness was found to be a source rather of weakness than of strength, owing to changed conditions of warfare; and then the mighty defences of steel, impervious to sword, lance, and arrow, passed away, to remain only as adjuncts of Parade and Pageant, or as examples in museums of a lost art in warfare and military history. As an aid to the study of History our interest in armour may be considered perhaps rather sentimental and romantic than practical or useful. But, if we consider the history of the Art of War, we shall find that our subject will materially assist us, when we remember that the growth of nations and their fortunes, at any rate till recent times, have depended to a large extent on the sword and the strength of the arm that wielded it.