Leonardo worked on the painting over an extended period that may have continued well beyond the initial commission circumstances. He never delivered it to whoever commissioned it — if anyone commissioned it — but kept it with him as he moved. When he left Florence for Milan again in 1506, the painting traveled with him. When he went to Rome in 1513, it traveled with him. It was, apparently, something he continued working on and was unwilling to separate himself from.
In 1516, Leonardo received an invitation from King Francis I of France to come to the French court. The invitation was an exceptional honor. Francis I was a Renaissance monarch who understood his patronage of artists and intellectuals as a statement of his own cultivation and France’s cultural ambitions. Leonardo, at sixty-four, accepted and traveled to France — taking with him, among other works, the Mona Lisa, the Virgin and Child with Saint Anne, and Saint John the Baptist. He settled at the Château du Clos Lucé, near Amboise, in the Loire Valley, where Francis I visited him regularly and provided him with an annuity and with the comfort of his final years.
Leonardo died at Clos Lucé on May 2, 1519. He was sixty-seven years old. The circumstances of the transfer of the Mona Lisa to French royal ownership after his death are not fully documented. The most widely accepted account is that Francis I purchased the painting from Leonardo’s estate, through the executor Salai or another associate. The sum mentioned in some accounts — four thousand florins — appears in secondary sources rather than a primary document. What is certain is that by the time of Francis I’s death in 1547, the Mona Lisa was in French royal possession. It remained there for the next two and a half centuries.