of revolution.  The massive and abiding art of Egypt ignored the personality of its gods and Pharaohs, distinguishing the various persons by dress, ornament, and attribute.  They had their canon of measurement, of which the length of the nose was probably the unit.[17] The Greeks, who often took the length of the human foot as unit, were long enslaved by their canon.  Convention made them adhere to a traditional face after they had made themselves masters of the human form.  The early figures of successful athletes were conventional; but, according to Pliny, when somebody was winner three times the statue was actually modelled from his person, and was called a portrait-figure:  “ex membris ipsorum similitudine expressa, quas iconicas vocant!” Not until Lysistratus first thought of reproducing the human image by means of a cast from the face itself, did they get the true portrait in place of their previous efforts to secure generalised beauty.[18] In fact, their canon was so stringent that it would permit an Apollo Belvedere to be presented by foppish, well-groomed adolescence, with plenty of vanity but with little strength, and altogether without the sign-manual of godhead or victory.  Despite shortcomings, Donatello seldom made the mistake of merging the subject in the artist’s model:  he did not forget that the subject of his statue had a biography.  He had no such canon.  Italian painting had been under the sway of Margaritone until Giotto destroyed the traditional system.  Early Italian coins show how convention breeds a canon—­they were often depraved survivals of imperial coins, copied and recopied by successive generations until the original meaning had completely vanished, while the semblance remained in debased outline.  Nothing can be more fatal than to make a canon of art, to render precise and exact the laws of aesthetics.  Great men, it is true, made the attempt.  Leonardo, for instance, gives the recipe for drawing anger and despair.  His “Trattato della Pintura"[19] describes the gestures appropriate for an orator addressing a multitude, and he gives rules for making a tempest or a deluge.  He had a scientific law for putting a battle on to canvas, one condition of which was that “there must not be a level spot which is not trampled with gore.”  But Leonardo da Vinci did no harm; his canon was based on literary rather than artistic interests, and he was too wise to pay much attention to his own rules.  Another man who tried to systematise art was Leon Battista Alberti, who gave the exact measurements of ideal beauty, length and circumference of limbs, &c., thus approaching a physical canon.  The absurdity of these theories is well shown in the “Rules of Drawing Caricatures,” illustrated by “mathematical diagrams."[20] Development and animation are impossible wherever an art is governed by this sterile and deadening code of law.  The religious art of the Eastern Church has been stationary for centuries, confined within the narrow limits of