The sense of naturalness and perfection hinted at in the Kritios Boy is fully realized in the Doryphoros (Spear-Bearer), by Polykleitos.  Originally cast in bronze, it now survives only in this Roman marble copy.

        Polykleitos formulated a set of rules for sculpting the ideal human form in a treatise called The Canon, a theoretical work which, like his Spear-Bearer, no longer survives.  But careful study of copies of his work reveals certain of his basic formulae.  In his published Canon, Polykleitos stated in mathematical terms the relationship of parts of the body with the whole, e.g., the proportion of finger with palm, palm with wrist, wrist with elbow, elbow with arm.  The proportion of the head with the rest of the body is one to seven (1:7).  The height of the head was used by Polykleitos as the unit of measurement for determining the overall height of the body: the Spear-Bearer is thus eight heads tall. The length of the foot is one-tenth of the figure’s height. This statue was viewed in antiquity as the definitive word on perfect proportions and was imitated by numerous artists.

        Polykleitos is often considered the first great aesthetician, or art theorist.  His aim, in his own words, was to produce the "eu" ( = "the good, the perfect").  In his sculptures there is a dynamic counterbalance between the tensed and relaxed parts of the body.  In all his known works the body stands firmly on one foot, the other bending slightly in perfect rest, producing the so called "Chiastic" pose.  His objective is "Symmetria", a Greek word whose meaning is "harmonious proportions".