In his Mona Lisa, the individual, a sort of miraculous creation of nature, 
represents at the same time the species; the portrait goes beyond its social 
limitations and acquires a universal meaning.  Although Leonardo worked on 
this picture as a scholar and thinker, not only as a painter and poet, the 
scientific and philosophical aspects of his research inspired no following.  
But the formal aspect - the new presentation, the nobler attitude and the 
increased dignity of the model- had a decisive influence over Florentine 
portraits of the next twenty years, over the classical portrait...With his 
Mona Lisa, Leonardo created a new formula, at the same time more monumental 
and more lively, more concrete and yet more poetic than that of his 
predecessors...Before him, portraits had lacked mystery;  artists only 
represented outward appearances without any soul, or, if they showed the 
soul, they tried to express it through gestures, symbolic objects or 
inscriptions.  The Mona Lisa alone is a living enigma;  the soul is there, 
but inaccessible.

This poetic mystery is increased by the close unity of the figure with the 
background landscape... CH.DE TOLNAY, Remarques sur la Joconde, in the 
'Revue des Arts", 1951.
