Complex sentence: Over the years there have been several alternative views among scholars; some have argued that Lisa del Giocondo was the subject of a different portrait, identifying at least four other paintings as the "Mona Lisa" referred to by Vasari.
Split into simpler sentences: Over the years there have been several alternative views among scholars as to the subject of the painting. Some have argued that Lisa del Giocondo was the subject of a different portrait, identifying at least four other paintings as the "Mona Lisa" referred to by Vasari.