Leonardo da Vinci (1452–1519) painted many major works. One difficulty in assessing them is that he experimented with a variety of different paints and surface preparations, many of which have deteriorated over time. Many of his works are famous for the way in which the characters of the people painted shine through. A fresco of The Last Supper (1495-1497) is considered by many, including the famous historian Vasari, to have been his masterwork, but unfortunately Leonardo used a technique that caused the work to deteriorate badly, and it has only been partially restored. Probably his most famous work is the Mona Lisa, a 1503 portrait of a woman that now hangs in the Louvre museum in Paris.