 In the 18th century it was returned to the Grand Duchy of Tuscany.Roccalbegna is home to several notable fortifications, such as the "Cassero Senese" (built in the 13th century by the Aldobrandeschi, renovated in the 15th century) and the "Rocca Aldobrandesca", located on the hill overlooking the town and the Albegna river (whence the town's name).Outside the town there is the large castle of Triana (known from 760), also owned by the Aldobrandeschi and then by the Sforza of Santa Fiora; it has maintained its medieval line of walls.