Francesco Melzi

When Leonardo da Vinci died in France in 1519, he left his manuscripts, drawings, and instruments to one man: Francesco Melzi, a young Milanese nobleman who had joined him as a teenage pupil and stayed to the end. Melzi had followed Leonardo from Milan to Rome and then to the French court, working as his assistant and companion through the master's final decade.

Melzi was a capable painter in his own right, trained in the Leonardo manner, but his lasting work was as a keeper. He carried the whole inheritance back to his family villa at Vaprio d'Adda, near Milan, and spent years sorting the loose pages of notes. From them he compiled the collection later known as the Treatise on Painting, the closest thing we have to Leonardo's own book on the subject.

The care ended with him. After Melzi died in 1570, his son Orazio saw little value in the papers and let them sit in an attic, and over the following decades the collection was broken up and scattered. Much of what survives of Leonardo's writing passed through Melzi's hands first.