Castello di Bibbiano, Medieval castle in Buonconvento, Italy

Castello di Bibbiano is a fortified structure near Buonconvento in Tuscany. The complex features a central square keep encircled by double walls with a protective ditch running along three sides of the perimeter.

The site dates to 850, when it belonged to the imperial legate Guinigi di Reghinari, a Longobard count. It passed to the Guiglieschi family until 1051, when Henry III assigned it to the Abbey of Sant'Antimo. In the early 16th century Cardinal Raffaello Petrucci, who held it from 1515, had it restored by Baldassarre Peruzzi; it later belonged to the Borghese, Chigi and Malavolti families.

The castle's architecture incorporates elements from different periods, including Guelph-style battlements and a gatehouse adorned with sandstone ashlar decorations.

The fortification sits several kilometers from Buonconvento town and can be reached by following the SS2 Cassia road. Local signage helps visitors navigate to the site.

The west corner holds a brick sentry box, crenellated and rounded on its inner face, where lookouts sheltered; the south-west and south-east sides are lower and less preserved, with only the corner brackets of lost sentry boxes remaining.