the average WHR never exited 'the fertile range' (from 0.67 to 0.80)." The Venus de Milo (130100BCE) has a WHR of 0.76; in Anthony van Dyck's Venus Asks Vulcan to Cast Arms for Her Son Aeneas (1630), Venus's estimated WHR is 0.8; and Jean-Léon Gérôme's Birth of Venus (1890) has an estimated WHR of 0.66. Body proportions in history The earliest known representations of female figures date from 23,000 to 25,000 years ago. Models of the human head (such as the Venus of Brassempouy) are rare in Paleolithic art: most are like the Venus of Willendorf bodies with vestigial head and limbs, noted for their very high waist:hip ratio of 1:1 or more. It may be that the artists' "depictions of corpulent, middle-aged females were not 'Venuses' in any conventional sense. They may, instead, have symbolized the hope for survival and longevity, within well-nourished and reproductively successful communities." The ancient Greek sculptor Polykleitos (c.450–420 BCE), known for his ideally proportioned bronze Doryphoros, wrote an influential Canon (now lost) describing the proportions to be followed in sculpture. The Canon applies the basic mathematical concepts of Greek geometry, such as the ratio, proportion, and symmetria (Greek for "harmonious proportions") creating a system capable of describing the human form through a series of continuous geometric progressions. Polykleitos may have used the distal phalanx of the little finger as the basic module for determining the proportions of the human body, scaling this length up repeatedly by to obtain the ideal size of the other phalanges, the hand, forearm, and upper arm in turn. Leonardo da Vinci believed that the ideal human proportions were determined by the harmonious proportions that he believed governed the universe, such that the ideal man would fit cleanly into a circle as depicted in his famed drawing of Vitruvian Man (c. 1492), as described in a book by Vitruvius. Leonardo's commentary is about relative body proportions with comparisons of hand, foot, and other feature's lengths to other body parts more than to actual measurements. Golden ratio It has been suggested that the ideal human figure has its navel at the golden ratio (, about 1.618), dividing the body in the ratio of 0.618 to 0.382 (soles of feet to navel:navel to top of head) ( is , about 0.618) and da Vinci's Vitruvian Man is cited as evidence. In reality, the navel of the Vitruvian Man divides the figure at