[Illustration: FIG. 25. Coude or Elbow-cop.] This assertion is not made without fully considering the real value of such work, which must fulfil all those essentials without which no true work of craftsmanship can have any merit. The first of these is that the work should fulfil its object in the best possible manner; secondly, that it should be convenient and simple in use; thirdly, that it should proclaim its material; and fourthly, and this is by no means the least important, that any decoration should be subservient to its purpose. To take our axioms in the order given, it may appear to the casual student that if armour were sufficiently thick it would naturally fulfil its primary reason for existence. But we find, on careful examination of plate armour, that there are other considerations which are of equal, if not greater importance. Of these the most noticeable is the 'glancing surface'. It is somewhat difficult to exemplify this by a line-drawing, though it is easy to do so with an actual example. Referring to the Maximilian breastplate (Fig. 24), we find that a lance, the thrusting weapon much favoured in the fifteenth and sixteenth centuries, would, on striking the breast be deflected along the grooved channel nearest to the point of impact till it reached the raised edge either at the top or at the sides, when it would be conducted safely off the body of the wearer. The same surface is to be noticed on all helms and helmets after the twelfth century, the rounded surfaces giving no sure hold for cutting or thrusting weapons. The Coude (Fig. 25) shows this same glancing surface used to protect the elbow, and, again, the fan-shaped plate on the outside of the knee effects the same result (see Frontispiece).[17] The great jousting helms are so constructed that the lance-point should glance off them when the wearer is in the proper jousting position, that is, bent forward at such an angle that the eyes come on a level with the ocularium or vision slit (Plate V, 5). These helms are also made of plates varying in thickness as the part may be more exposed to attack. The Great Helm in the possession of Captain Lindsay of Sutton Courtenay, near Abingdon, has a skull-plate nearly a quarter of an inch thick, for, in the bending position adopted by the wearer, this portion of the helm would be most exposed to the lance. The back-plate is less than half that thickness. This helm is one of the heaviest in existence, for it weighs 25 lb. 14 oz. Again, we may notice the overlapping Lames or strips of steel that are so frequently used for Pauldron, Rerebrace, Vambrace, Soleret, and Gauntlet; all present the same surface to the opposing weapon, and, except in the case of the Taces, where the overlapping from necessity of form must be in an inverse direction, the chance of a weapon penetrating the joints is reduced to a minimum (Fig. 23). A portion of the pauldron which is designed for this glancing defence, and for this only, is the upstanding