Castelvecchio's history is intertwined with those of the castles and fortresses that overlook the valley of the Orcia river, the historical land of perpetual Sienese battles. The past, rich of struggles and adventure, can still be felt within the thick, strong walls that were raised for fortification during long periods of unrest: From the Etruscans of the Iron Age, to the Germanic invasions by the Lombards, and all the way through to the Middle Ages and the French domination.
The first official historical documentation of the estate dates back to 1279 with the death of Napoleon Visconti who is said to have died within the walls of Castelvecchio castle. However, the origins can be dated back at least to 1064 when Castelvecchio was first mentioned by historical texts as being in a strategic position along the Via Franchigia. At that time it was reported that the inhabitants of Castelvecchio had joined forces with those of Borgo del Formone in the attempt to protect the land, both against the overflow of the Fermone and Orcia rivers as well as against the attacks of outlaws.
During the Medieval period Borgo di Castelvecchio was at times a spectator and at times a participant of the ongoing battles between different feudal lords governing the Republic of Siena, Orvieto and Florence. Castelvecchio was owned by the powerful medieval family of the Visconti from 1279 to 1339 and from 1369 to 1429 by the Salimbeni family, who were known to have switched loyalty between the two opposing factions, the Guelphs and the Ghibellines, in a game of changing alliances. In the XVII century 4 farms belonging to the Castelvecchio estate were acquired by the Bandinelli family who were the Lords of Siena and owners of Montalcino, Castiglion del Bosco, Abbadia Ardegna e Campiglia. The Burbon del Monte Marquises were in possession of the estate until it was gifted as dowry of the young Antonietta who had been wedded to Count Aleberto Morelli Ademari in 1900.
In1959 the whole property was acquired by the De Angelis family. Today it belongs to the De Angelis Gaetani d'Aragona. In the same territory another important castle dominated the Orcia Vally. The Perignano Castle, who's ancient front gates still protect the entrance of the Villa, was destroyed in the last violent conflict against the Sienese in 1456.