The Caro stream was continuously exploited up until the middle of the 20th century for milling cereals and chestnuts. During the Middle Ages, this stream was also regularly used for wool fulling.
In 1144 and then in 1292, mills and fulling mills on the Caro are documented, all belonging to the Counts Aldobrandeschi, the parish church of Santa Fiora, and the monastery of the Holy Trinity.
This mill retains traces of the gate fortification and of a good number of inscriptions in the medieval walls.
During the Sforza’s rule, the mill was equipped with a service aqueduct that also supplied the Capuchin Poor Clares.