Careless treatment of the heraldry, with which it is, nevertheless, obliged to deal more or less, sooner or later, seems to pervade applied art and to spoil what is otherwise meritorious work. Doubtless much of the mischief arises from fear lest improving the drawing or composition may violate heraldic rules; and this brings us to the necessity of acquiring so much knowledge of the systematic side of heraldry as will suffice to show what points are really essential (and therefore to be carefully preserved and if need be accented), and what, on the other hand, may be modified or ignored. This may best be done by study of the system of heraldic description known as blazon, which is described further on. But before proceeding to do so it will be necessary to deal first with an heraldic composition as a whole. CHAPTER II Evolution of Shield Forms The armorial group, called an “Achievement” of Arms, principally consists of the shield and the crest, the latter supported on its helm, and accompanied by the mantling or lambrequins, and in addition, mottoes, coronets, supporters and other accessories proper to the occasion may form part of its composition. The term “achievement” (sometimes corrupted into hatchment) may be applied to any heraldic group whether it be a complete presentation of full armorials or only a selected part of them. In the simple arrangement of shield, helmet and crest, the proportion of the parts to each other remained fairly constant from the end of the thirteenth century down to the Renaissance, that is to say throughout the whole mediaeval period, and may be taken roughly to be rather more than two-fifths of the whole height for the shield and rather less than three-fifths for the helmet and crest. This, it need hardly be said, must not be taken for actual measurement, but only as suggesting the relative weight in the design of its component parts. The result of these proportions is to bring the helm a little above the actual middle of the composition, and its place is then found to be a very satisfactory one, in which it serves as a central point on which the other objects group themselves. There is also seen to be due scope for the clear definition of the details of both arms and crest, while there is an appropriate suggestion of dignity in the whole effect. The principal artists of the Renaissance, Dürer above all, appear to have fully appreciated this, similar proportions appearing in the best type of Renaissance work as in that of the Gothic period. Such proportions were no doubt suggested by those of the actual things themselves, but not wholly so; for in other cases the object of the artist was rather to display the armorials to the best effect than to copy their appearance when they were being used in another way.