The canvas which depicts the Nativity of the Virgin Mary on the main altar of the church of the Propositura was painted by Giuseppe Nicola Nasini in the early 18th century. Critics consider the work one of the Nasini's best in terms of compositional clarity and inventive freshness. Surrounded by female figures who have just witnessed the birth, Saint Anna holds the new-born Maria on her lap. A kneeling woman prepares a bath for the infant, while a light shines down from the figure of God the Father and some angels in a sky full of clouds above.