Artistic canons of body proportions
An artistic canon of body proportions (or aesthetic canon of proportion), in the sphere of visual arts, is a formally codified set of criteria deemed mandatory for a particular artistic style of figurative art. The word 'canon' (from , a measuring rod or standard) was first used for this type of rule in Classical Greece, where it set a reference standard for body proportions, so as to produce a harmoniously formed figure appropriate to depict gods or kings. Other art styles have similar rules that apply particularly to the representation of royal or divine personalities. Ancient  Egypt. Danish Egyptologist Erik Iverson determined the Canon of Proportions in classical Egyptian painting. This work was based on still-detectable grid lines on tomb paintings: he determined that the grid was 18 cells high, with the base-line at the soles of the feet and the top of the grid aligned with hair line, and the navel at the eleventh line. These 'cells' were specified according to the size of the subject's fist, measured across the knuckles. (Iverson attempted to find a fixed (rather than relative) size for the grid, but this aspect of his work has been  dismissed by later analysts.) This proportion was already established by the Narmer Palette from about the 31st century BCE, and remained in use until at least the conquest by Alexander the Great some 3,000 years later. The Egyptian canon for paintings and reliefs specified that heads should be shown in profile, that shoulders and chest be shown head-on, that hips and legs be again in profile, and that male figures should have one foot forward and female figures stand with feet together. Classical Greece. Canon of Polykleitos. In Classical Greece, the sculptor Polykleitos (fifth century BCE) established the Canon  of Polykleitos. Though his theoretical treatise is lost to history, he is quoted as saying, "Perfection ... comes about little by little () through many numbers". By this he meant that a statue should be composed of clearly definable parts, all related to one another through a system of ideal mathematical proportions and balance. Though the "Kanon" was probably represented by his "Doryphoros", the original bronze statue has not survived, but later marble copies exist. Canon of Lysippos. The sculptor Lysippos (fourth century BCE) developed a more gracile style. In his , Pliny the Elder wrote that Lysippos introduced a new canon into  art: signifying "a canon of bodily proportions essentially different from that of Polykleitos". Lysippos is credited with having established the 'eight heads high' canon of proportion. Praxiteles. Praxiteles (fourth century BCE), sculptor of the famed "Aphrodite of Knidos", is credited with having thus created a canonical form for the female nude, but neither the original work nor any of its ratios survive. Academic study of later Roman copies (and in particular modern restorations of them) suggest that they are artistically and anatomically inferior to the original. Japan in the Heian period. Canon of Jōchō. Jōchō (定朝; died 1057 CE), also  known as Jōchō Busshi, was a Japanese sculptor of the Heian period. He popularised the "yosegi" technique of sculpting a single figure out of many pieces of wood, and he redefined the canon of body proportions used in Japan to create Buddhist imagery. He based the measurements on a unit equal to the distance between the sculpted figure's chin and hairline. The distance between each knee (in the seated lotus pose) is equal to the distance from the bottoms of the legs to the hair. Renaissance Italy. Other such systems of 'ideal proportions' in painting and sculpture include Leonardo  da Vinci's Vitruvian Man, based on a record of body proportions made by the architect Vitruvius, in the third book of his series . Rather than setting a canon of ideal body proportions for others to follow, Vitruvius sought to identify the proportions that exist in reality; da Vinci idealised these proportions in the commentary that accompanies his drawing: