The Fort of San Paolino looms imposingly over the town of Ripafratta, which always found itself on the border between the territories of Pisa and Lucca. One of the first towers of the fortified Ripafratta was built as early as 970, probably under Pisan rule; in 1100 it was expanded massively to become one of the most unmistakable elements of the landscape, even assuming the form of a castellated fort. A true theatre of war, it was conquered by the Florentines, who passed it from Pisan to Lucchese hands as a gift to their allies.
In the fifteenth century it was further fortified so as to be almost impregnable to the Pisans. The advent of firearms made such renovations necessary, and the Medici turned to their architect Giuliano da Sangallo to oversee them and render the stronghold even stronger. Even today one can clearly see the difference between the original part and the part from the fifteenth century, especially in the brick additions which contrast with the darker stone of the earlier sections.
When the town diminished in importance as a strategic position, the fort was left to itself. Today we can see the emblems of various governors, from Pisa or Florence, above the gate that leads to the training ground inside, while the towers that constituted a part of the ancient castle remain standing: the torre del Centino and the torre Niccolai.
On account of its condition, the fort can be visited today only with some precautions, but the local association organises guided tours for certain days of the year.