Castel del Piano located within the Province of Grosseto Province. The location of ancient origins, documented thanks to numerous testimonies and present findings unearthed during excavations of diatomaceous earth. It is taken into consideration within the historical writings with the ancient name of "Casale Plana" in some documents of Beloeil of Monte Amiata, belonging to 890. Between 1175 to 1331 became part of the territories of aldobrandeschi of Santa Fiora. At Siena collapse domain became part of the family of Cosimo de 'Medici.