Leonardo's second long-term companion was Francesco Melzi, a minor noble from Florence who joined Leonardo's household in 1505, at age fifteen. Melzi appears to have been a more talented painter than Salai, and less of a handful! Melzi was also supposedly a very handsome young man, like Salai.
A number of paintings and drawings by Melzi survive, including a portrait of Leonardo. Leonardo-inspired elements are clearly visible, such as the serene smiles on the faces of the women, and fantasy backgrounds with craggy mountain peaks and sinuous rivers. Melzi's work, however, lacks depth. His paintings appear almost flat, and his sense of proportion is less well defined. His women appear sweet, not mysterious like those in Leonardo's paintings. Clearly, Melzi had only a minor talent when compared with his master painter.
Melzi remained with Leonardo until Leonardo's death, upon which he became the executor of Leonardo's will. Leonardo left the bulk of his estate to Melzi, including his clothes, the paintings in his possession, and perhaps most importantly, his notebooks. Melzi faithfully kept the notebooks safe until the end of his life, around 1570, and is thought to have organized some of them into a longer version of A Treatise on Painting. Unfortunately, by the time of Melzi's death the importance of the notebooks had been forgotten, and they were scattered by Melzi's heirs.
The long-term relationships that Leonardo maintained with both Salai and Melzi indicates that while they were perhaps apprentices, they were probably his lovers as well. Both were reputed to be particularly handsome, as was Leonardo himself in his youth. Such teacher-student relationships were not uncommon in the Renaissance. Both men traveled with Leonardo around Italy, and Melzi accompanied him to France at the end of his life. Although no direct evidence exists to prove that Leonardo and Melzi had a sexual relationship, the fact that Leonardo named Melzi as his heir and left his precious notebooks in Melzi's care indicates the deep love and trust he felt for his former student.