The Fortezza delle Verrucole, at just three kilometres from the chief town, is set on a hill in the town of San Romano in Garfagnana. Many remains of the building still exist and it was built by the Gherardinghi, a feudal seigniory fighting against the Bacciano for the control of San Romano.

The Counts Gherardinghi built the fortress around the XI-XII centuries to live there and dominate their territory. This powerful family inhabited the Verrucole until the year 1285, when the Republic of Lucca bought the building. At that time, the castle was composed of two different structures, the Rocca Quadra and the Rocca Tonda, set on the two ends of the hill and surrounded by walls.
The "Castrum Verrucolae Gherardinghi" (this is the name reported in an imperial bull of 1376 issued by Charles IV) was later ceded to Spinetta Malaspina, a member of one of the other feudal seigniories fighting at the borders between Tuscany, Liguria and Emilia. After the conflict between Guelfs and Ghibellines ended, the Florentines took the fortress in 1430. Lucca got it four years later and, finally, the Estensi, who put San Romano and its territories under their authority, owned it.
A document of 1487 cited the castle and it carefully reported on the structure and the different functions of the two strongholds that constituted it. From here, it can be learnt that the Rocca Quadra was a watchtower scarcely furnished and equipped with very few weapons. Instead, the Rocca Tonda was better equipped to be a residence and for the possible quartering garrisons. Moreover, it benefited from a better view over the valley bottom of the Garfagnana and over the landscape of the Apuan Alps.
It is thought that the Rocca Tonda was the first to be raised on the hill. In effect, the chapel of the castle is set at its foot and the embattled walls of the that surround also the remains of the Rocca Quadra start from it. In the XVII century, the Estensi settled that two bastions substituted the Rocca Quadra. The Dukes of Ferrara highly regarded the Fortezza delle Verrucole and they always garrisoned it with a small detachment of their army with some artillery, too. In the Moddern Age, a period of peace and stability started in Garfagnana. Therefore, the fortress was adapted as a prison.