Doryphoros of Polyclitus, Roman copy in marble of bronze original, c. 450-440 B.C.
The first datable professional treatise on sculpture was the Canon of Polyclitus, probably written during the third quarter of the fifth century B.C. The Canon was the most renowned ancient treatise on art, and enough information is preserved about it in extant ancient texts to enable us to form some conception of its content. The aim of the Canon, was not simply to explain a statue but also to achieve to kallos, the beautiful and to eu (the pefect or the good) in it. The secret of achieving to kallos and to eu lay in the mastery of symmetria, the perfect commensurability ” of all parts of the statue to one another and to the whole.