He began the Mona Lisa around 1503. He could not finish it — or would not. He carried it with him to France and worked on it until the day he died. What kept holding him there?
Leonardo da Vinci was a man for whom painting was not a craft, not even an art, but an instrument of knowledge. He drew the heart in order to understand how the blood beats. He studied the face in order to catch exactly where, in which muscle, a smile is born. The Last Supper is not a religious picture; it is a psychological experiment — twelve different reactions to one and the same piece of news. Look at the apostles: each is a separate human being at the moment of shock.
He was born in 1452, the illegitimate son of a notary — and that decided everything. No inheritance, no guild, no obligations to tradition. Only freedom, and an endless curiosity. In Florence, in Verrocchio's workshop, he painted an angel better than his master could. In Milan, at the court of Ludovico Sforza, he was military engineer, deviser of festivities and painter all at once. He designed canals, tanks, flying machines — most of them never built. What interested him was the conception, not the execution.
Hence so much left unfinished. The Adoration of the Magi — abandoned. The Battle of Anghiari — destroyed. Saint Jerome — incomplete. This is not laziness. It is the mark of a man whose mind outruns his hands.
The mystery of the Mona Lisa is not the smile. The mystery is that in five hundred years no one has managed to explain why the picture will not let go of us. Leonardo knew something about the human face, about light, about the way the brain completes what is not on the canvas. And he took that knowledge with him.