In later life, Botticelli was one of the followers of the deeply moralistic friar Girolamo Savonarola who preached in Florence from 1490 until his execution in 1498, though the full extent of Savonarola's influence remains uncertain.[6]
"Like much of Florence, Botticelli had come under the sway of Savonarola and his art had transformed from the decorative to the deeply devout - The Mystical Nativity (c. 1500-1501) [for example] bears all the signs of this change"[7]
"The story that he burnt his own paintings on pagan themes in the notorious "Bonfire of the Vanities" is not told by Vasari, who nevertheless asserts that of the sect of Savonarola "he was so ardent a partisan that he was thereby induced to desert his painting, and, having no income to live on, fell into very great distress. For this reason, persisting in his attachment to that party, and becoming a Piagnone[8] he abandoned his work."
Botticelli biographer Ernst Steinmann searched for the artist's psychological development through his Madonnas. In the "deepening of insight and expression in the rendering of Mary's physiognomy", Steinmann discerned proof of Savonarola's influence over Botticelli. (In Steinmann's work the dates of a number of Madonnas were placed at a later point in the artist's life). Steinmann disagreed with Vasari's assertion that Botticelli produced nothing after coming under the influence of Savonarola, believing rather that the spiritual and emotional Virgins painted by Sandro followed directly from the teachings of the Dominican monk.