The Sidney Sonnino Castle at the edge of Montespertoli is a 19th-century neo-medieval structure built for the Sonnino family, whose most famous member — Baron Sidney Sonnino — twice served as Prime Minister of Italy and represented the country at the Paris Peace Conference after World War One. The castle is set in the typical Chianti landscape of vineyards and olive groves and is visible from the approach road to town.
The property is private and not regularly open to visitors, but the exterior and grounds can be admired from the road. It is a good example of the romantic historicism popular among wealthy Italian families in the late 19th century, when medieval fortress aesthetics were fashionable. The Sonnino family had significant political and social influence in liberal Italy, and the castle served as a meeting point for leading political figures of the era.