This castle was first mentioned in 1058. It was owned by Volterra’s bishops for a long time, until its inhabitants pledged allegiance to the municipality of Volterra in 1204.
The small “borgo” of Sasso was the reason behind the tragic looting of Volterra, because this is where the alum quarry that Florence wanted to take over because of the material’s potential in the process of leather tanning and weaving was discovered.

Alum was originally imported from Minor Asia, but once the Turks invaded that area that trade had to stop. That’s why the Florentines were desperately looking for an alum quarry, which at that point had become a key element of their economy. So they decided to subdue Volterra in order to get to the quarry in Sasso.

The town of Sasso Pisano developed itself around the castle, which is located at the Eastern tip and definitely deserves a visit for its evocative atmosphere. The stone houses look like they are directly coming out of the rock and all have a set of outside stairs connecting the ground floor to the first floor. The town is located on the very South tip of the municipality of Castelnuovo and still has a series of underpasses spicing up its circular structure.
The castle opens up on a small paved “piazza” with a church and a rectory.

Visitors can’t miss the two important landmarks just outside the town towards the sea: the archeological area Terme Etrusche del Bagnone (in English “Bagnone Etruscan Thermal Baths”) and the geothermal route with its small geysers and hot water puddles.

As a matter of fact, Sasso Pisano is the one town which best shows the geological nature of the area, with its vapors and springs of boiling water.
If you’d like to go for a dip, make sure to check out the “Biolake” at the entrance of the town.