The octangular bell tower, the second most famous in the city after the
Leaning Tower, most likely dates to 1170. There is no proof, but, as in the case of its other more famous counterpart, the architect seems to be
Diotisalvi. Originally it was separated from the nearby buildings. It is also slightly tilting; the base is under the current street level. The lower part starts at the top of each side with blind arches including lozenges. The bell has instead a good plan, with a single mullioned window on each side, and is surrounded by a gallery with small arches supported by columns. The cusp has a pyramidal shape. The polychrome effect was obtained by using stones from different locations. ==External links==