The decline of this family started with the death of Aldebrandino VIII (1216). At the end of the 13th century Orvieto conquered the Castle of Capalbio artd the surrounding lands. Once the political authority of Orvieto disappeared, Capalbio was given by the Aldobrandini family to the Republic of Siena, thui falling under the Orsini's rule. In 1416 Capalbio was definitively conquered by Siena and this was a prosperous and active period. The fight between France and Spain dominated the events of the 16th century, when also Siena lost its freedom under
the Medici power. Capalbio surrendered to the Spanish Prince of Marignano, ally of the Medici, in 1555. The Medici's conquest marked for Capalbio the beginning of a long period of economic stagnation. Like in the rest of Italy, the 17th century opened under the banner of decadence and no significant event took
place in Capalbio. Once the Midiri family finished in 1737, the Hapsburg Empire reached Tuscany as well with the Lorena family. Under Pietro Leopoldo di Lorena Capalbio was annexed to Manciano; later on, in 1842, Pietro Leopoldo II put it
under Orbetello. The state of the territories of Capalbio was disastrous between the 18th century and the 19th century. The cultivated lands turned again into marshes, malaria spread out again and the area progressively depopulated. At the end of the 19th century Capalbio territory was divided into two large estates, on one side the estate of the Collacchioni family and on the other side the estate of the Vivarelli-Colonna family. Long walls marked the border between the two estates. After the second Independence War Capalbio, together with the rest of Tuscany, became part of Italy in 1860. In 1952 the enforcement of the Agrarian Reform, preceded by the creation of the "Ente Maremma" (local agricultural board), succeeded in recovering local agriculture to modern development. Capalbio will become self-reliant again in 1960.