The central part of Palazzina della Viola was built toward the end of the 15th century by Annibale Bentivoglio to make it a place of delight for his family. Once the Bentivoglio family was banished from Bologna, the Palazzina - a specimen of 15th century Bologna architecture tinged with Tuscan grace - was passed on to the Salicini family. Then, in 1540, it was purchased by Cardinal Bonifacio Ferreri to join it to the Collegio dei Piemontesi, whose headquarters were in the adjacent old building of the Orto Botanico (Botanical Garden). It was used for different purposes until 1803 when Napoleon's government allocated it to the School of Agriculture of the University, headed by Filippo Re. When it was owned by the Ferreri family in the 16th century, the Palazzina received paintings by Aspertini, Innocenzo da Imola, Prospero Fontana and others. There are three frescoes by Innocenzo da Imola in the first floor loggias. The depict mythological legends and are the only profane paintings executed by the famous painter. The first fresco, in the loggia looking to the east, depicts "Apollo and Marsyas"; the second and third, in the loggia looking to the south, are representations of "Diana and Actaeon" and "Diana and Endymion". A ceiling made of cornices for paintings attributed to Amico Aspertini is on the ground floor. The large hall is distinguished by the grandiose fresco by Prospero Fontana, framed in an architectural composition, in which episodes of the "Legend of Pope Sylvester and Emperor Constantine" are depicted. The tall frieze filled with putti that runs all around the hall is believed to be a work by Nicolò dell’Abate.