Casa Buonarroti. Casa Buonarroti is a museum in Florence. The building was a property owned by the sculptor Michelangelo, which he left to his nephew, Lionardo Buonarroti. The house was converted into a museum dedicated to the artist by his great nephew, Michelangelo Buonarroti the Younger. Its collections include two of Michelangelo's earliest sculptures, the Madonna of the Steps and the Battle of the Centaurs. A ten-thousand book library includes the family's archive and some of Michaelangelo's letters and drawings. The Galleria is decorated with paintings commissioned by Buonarroti the Younger and created by Artemisia Gentileschi and other early seventeenth-century Italian artists.