The pointed shield was one of the most satisfactory shapes for the display of a single coat of arms, but it became inconvenient, in most cases, when two coats were impaled together or when quarterings were involved, the restricted base rendering it extremely difficult to deal with objects in that part of the shield. The seals and monuments naturally represent shields as very flat, but they were not actually so, but were almost always curved in section to a greater or less extent, and in one or more directions; for armour was designed to deflect a blow rather than to directly resist it, this being one of the ordinary principles on which most kinds of defence are based. As we have seen in the Norman shields, the curve was at first simply from side to side, afterwards, in order to prevent a blow from glancing downwards, the lower part of the shield was made to project, and finally the top was brought forward so that the shield had a double curvature, convex from side to side and concave perpendicularly (Fig. 13). A large shield called a pavoise was used for fighting on foot, a partial reversion, for definite practical reasons, to the long shield of the Normans. Like the Norman shields, it in some cases had a pointed or rounded base, while in others it was roughly rectangular, its most marked characteristic being the large and projecting rib whose hollow served on occasion to accommodate a supporting stake (Figs. 14 and 15). It was provided with handgrips and, in most cases, with a guige by which it could be slung on the shoulders or carried on the back when not in use. Besides those which were painted with subjects which extended over the whole surface in the usual way, others were decorated with small painted shields drawn on the larger one. [Illustration: FIG. 13.] [Illustration: FIG. 14. Pavoise. Afli. Violet-le-duc.] [Illustration: FIG. 15. Back of Fig. 14.] The term pavoise is sometimes given to the large decorative shields (of various shapes) which were made in considerable numbers in the sixteenth and seventeenth centuries, especially in Italy; but there is no doubt that the term, in strictness, should be confined to this special defence of the foot-soldier. A shield with a sharp arris or ridge and a round base is said to have been the last form to be used in actual war (Fig. 16), and is interesting as the prototype of the ridged Renaissance shield, which became of such decorative value, especially when modelled in relief, because of the play of light and shade which it afforded (Fig. 16A. See also Figs. 20 and 21). [Illustration: FIG. 16.--Fifteenth Century.] It will, of course, be understood that the various shapes of shields, as they were gradually evolved one from the other, did not in representation supersede their predecessors altogether, however more or less completely they may have done so as actual defence, and a considerable amount of overlapping took place in this as in other heraldic fashions.