Built between 1628 and 1629. During the second half of the 1800s it was the residence of Princess Maria Valentini Bonaparte, who made it the very hub of the town’s cultural scenario. Inside are frescoes by Giovanni Andrea Carlone (17th cent.) and Felice Giani (18th-19th cent.). The palazzo is now the seat of the August Communal Library, founded in 1582 by Prospero Podiani. It preserves 300,000 works, including 3,325 manuscripts, 1,326 incunabula, 645 Aldine editions and 16,550 16th-century editions, as well as a precious collection of antique maps.