San Colombano Castle, Medieval castle in San Colombano al Lambro, Italy

San Colombano Castle stands in San Colombano al Lambro, province of Milan. Its present layout is attributed to Frederick Barbarossa, who rebuilt it in 1164 after destroying it, adding the walled suburb called Magnum suburbium. Galeazzo II Visconti had it transformed from 1370: the outer walls were faced in new brick, and a central keep was raised inside the rocca.

The castle existed by the 10th century, guarding the route between Pavia and Corte Olona and named in a 1034 testament of Ariberto. Frederick Barbarossa destroyed it during his second Italian campaign, then rebuilt it in 1164 with a walled suburb, the Magnum suburbium. From 1370 Galeazzo II Visconti transformed it, adding bastions and a central keep; under the Visconti it served as a state prison, where Lodrisio Visconti was held in 1338.

The name San Colombano refers to the Irish monk Columbanus, linked in local tradition to the monastery of Bobbio founded in the same period; the castle itself is documented from the 10th century. The borgo grew around the fortress, and Galeazzo II Visconti's 1373 donation to his wife Bianca of Savoy granted the commune special statutes.

The castle sits on a hill and can only be reached on foot via stairs and uneven terrain, so sturdy shoes are a good idea. It is about 19 miles (30 km) from Milan, making it easy to visit by car.

The hill on which the castle stands is part of the only DOC wine production zone within the Metropolitan City of Milan. This means a visit to the castle can naturally lead to a walk through working vineyards just a short distance away.