In 1295 Simone dei Cacciaconti, Lord of Montisi, left his estate in Montisi to the Hospital of St. Maria della Scala in Siena, in his last will.
In the next century the Hospital built a small fortress with a high tower on the Western boundary of the village. It was to be used as a "Grancia", a granary for the storage of the produce grown on the property.
In 1775 Pietro Leopoldo, Grand Duke of Tuscany, issued an order to sell the estate of the Hospital, including the Grancia of Montisi. It was bought by Jacopo Mannucci Benincasa in 1778 and has remained in the family to this day.
In June 1944, during World War II, the beautiful fortified tower of the Grancia was dynamited at its base and completely destroyed.