Relief in metal work, cast or wrought, was very fully employed in the Renaissance monuments in place of the flatter treatment which preceded it. The mediaeval memorials more frequently employed the flat decoration done in Champlevé enamel fixed into the spaces of sculptured stone, or else the incised metal slab, somewhat similar in its method of production, which is known as a Monumental Brass. These are so comparatively numerous and of such admirable workmanship as to form one of the most interesting and instructive means of studying most that pertains to good heraldry. They were executed with great care, and afford examples of almost every kind of application of arms and badges to costume. Their wealth of heraldic lore is ably set forth in the works of Creeny, Waller, and others, and a single illustration must suffice here. Fig. 178 is the interesting brass to the memory of Sir John de Brewys, which is in many respects typical. The figure of the knight in his armour, his hands in an attitude of prayer, his head resting on his great helm, which bears his crest, and his feet on a couchant lion. Around him are shields of his arms six times repeated, and between them on little scrolls the words “Jesus” and “Mercy” many times occur. The method of work is very similar to that of the Champlevé enamels, allowing for the difference in scale, the lines being boldly incised in the metal with chisel-like tools and then filled in with black or colour much after the way of the niello and enamel of the smaller and more precious work, a hard waxy composition being used as the colouring material.