The centre of Palazzo dei Pio facade is characterized by the Clock Tower, the main entrance to the complex. The construction of the Tower started in 1577 on the old keep of the Castle.
After a partial collapse in 1597, the building was rebuilt in the present form between 1625 and 1637 on a project by Gildo Fassi. The tower, which has kept part of the 15th -century monumental vestibule with the great portal with ashlar Doric pillars, is characterized by a composite vertical shape with overlapping masses which decrease in size upward and end with a pinnacle opened in four arches and topped by a little copper-plated dome.
