A colony of Lucca, probably founded in the XIIth century, Pietrasanta grew to become, in the XIIIth, the region's sole political centre. Castruccio Castracani promoted the town's fortification, renovating the ancient rocca di Sala and building, in 1324, the Rocchetta that he dedicated to his son Arrigo. During the XVth century Lucca defended its Versilia holdings against Florentine interferences by joining forces with Genova and supporting the King of France, Charles VIIIth. At the end of the century, however, the war between Florence and Sarzana brought Pietrasanta and the whole of central Versilia under the control of the Medici. The Florentines fortified the town, whose walls and towers had been badly damaged during the war. Castracani's Rocchetta, that had been completely destroyed, was rebuilt: it retained though the old name of "Arrighina", as it is called to this day.
In the middle of the XVIIIth century the Rocchetta, that had by then lost all military significance, was deprived of all ammunition, that was instead transferred to the Torre del Salto della Cervia and of Cinquale. The Rocca di Sala was sold in 1779 by Leopoldo I, Grand Duke of Tuscany, to Andrea and Giovanni di Dio Luccetti of Pietrasanta for 950 scudi.