The palace, seat of the Provincial administration, called "Palace of the dark arcade" derives its name from the typical dimness of its arcades. Its building is due to the Malvezzi, an illustrious family present in town since the 12th century, actively participating in the town's political life, with important posts supporting the Guelph party and later the Bentivoglio's. In 1488, however, the Malvezzi took part in the conspiracy against the Bentivoglio, hatched by the Marescotti and were thus banished from town, after being deprived of their property. Only in 1506, following the overthrowing of the Bentivoglio and the town's incorporation in the Papal States, were they able to return to Bologna and take back again the Senatorial title and all their properties. The reconstruction of the palace started in 1560 following the design by Bartolomeo Triachini. Of the most relevant renovation work, let us recall here the addition of the staircase promoted in 1725 by Marquis Giuseppe Malvezzi de'Medici and attributed in the past to architect Alfonso Torreggiani. In reality, the latter merely followed the construction work, while the drafting of the project should be assigned to Francesco Bibiena. Between 1852 and 1853 the Malvezzi promoted several decoration works on the main floor, by assigning them to stage designer Francesco Cocchi, figure painters Antonio Muzzi and Girolamo Dal Pane and ornamentalists Giuseppe Badiali, Andrea Pesci and Luigi Samoggia. In 1931 the palace was purchased by the Provincial administration of Bologna. The furnishings and the precious library, on sale for around 100,000 lire, were not included in the acquisition and disappeared, sold in the antique market. Just after the palace acquisition the technical office of the Province drafted a detailed renovation plan and the restoration work was carried out under the direction of architect Emilio Boselli. Large-scale changes mainly involved Bibiena's staircase. The decorated rooms on the main floor kept instead their original structure and are now used as official reception facilities.