The fact seems to be that Greek and Italian plastic art followed different lines of development, owing to the difference of dominant ideas in the races, and to the difference of social custom.  Religion naturally played a foremost part in the art-evolution of both epochs.  The anthropomorphic Greek mythology encouraged sculptors to concentrate their attention upon what Hegel called “the sensuous manifestation of the idea,” while Greek habits rendered them familiar with the body frankly exhibited.  Mediaeval religion withdrew Italian sculptors and painters from the problems of purely physical form, and obliged them to study the expression of sentiments and aspirations which could only be rendered by emphasising psychical qualities revealed through physiognomy.  At the same time, modern habits of life removed the naked body from their ken.

We may go further, and observe that the conditions under which Greek art flourished developed what the Germans call “Allgemeinheit,” a tendency to generalise, which was inimical to strongly marked facial expression or characterisation.  The conditions of Italian art, on the other hand, favoured an opposite tendency—­to particularise, to enforce detail, to emphasise the artist’s own ideal or the model’s quality.  When the type of a Greek deity had been fixed, each successive master varied this within the closest limits possible.  For centuries the type remained fundamentally unaltered, undergoing subtle transformations, due partly to the artist’s temperament, and partly to changes in the temper of society.  Consequently those aspects of the human form which are capable of most successful generalisation, the body and the limbs, exerted a kind of conventional tyranny over Greek art.  And Greek artists applied to the face the same rules of generalisation which were applicable to the body.

The Greek god or goddess was a sensuous manifestation of the idea, a particle of universal godhood incarnate in a special fleshly form, corresponding to the particular psychological attributes of the deity whom the sculptor had to represent.  No deviation from the generalised type was possible.  The Christian God, on the contrary, is a spirit; and all the emanations from this spirit, whether direct, as in the person of Christ, or derived, as in the persons of the saints, owe their sensuous form and substance to the exigencies of mortal existence, which these persons temporarily and phenomenally obeyed.  Since, then, the sensuous manifestation has now become merely symbolic, and is no longer an indispensable investiture of the idea, it may be altered at will in Christian art without irreverence.  The utmost capacity of the artist is now exerted, not in enforcing or refining a generalised type, but in discovering some new facial expression which shall reveal psychological quality in a particular being.  Doing so, he inevitably insists upon the face; and having formed a face expressive of some defined quality, he can hardly give to the body that generalised beauty which belongs to a Greek nymph or athlete.