Some researchers believe that the Mona Lisa is actually at least partly composed of Leonardo’s male assistant, and sometime lover Salai. Apparently, Leonardo worked on the painting over a period of several years. He added, and changed elements from multiple sources. It was common for the Masters in art to compose a picture from multiple people as models – as it was believed that one might have a more perfect nose, another a more beautiful pair of eyes, etc. There was a search for the perfect in beauty, as a pursuit of truth.