Attached to the west side of the north gate tower was a medieval house (14th century), to which the manor house known as Casa del capitano or del gastaldo (palazzo Ridolfi, then Bozza-Marrubini) of 15th-century origin was later connected, heavily renovated into a manor house at the end of the 1500s.

It was part of a long building with round arches that extended almost to the south gate tower and was used as housing for staff and service offices (capitano e gastaldo). The ground floor retains the ancient arches of the portico, and on the first floor, a trifora adds elegance to the arched windows.

The palace is internally frescoed with pictorial cycles by Gio. Francesco Zamolo da Venzone (1704-1712), important not so much for the mythological scenes (Morte di Cleopatra, Telamone, Didone ed Enea, Scena mitologica), but for the depictions of the urban scenario of the castle and other buildings of the time within the walled circle. The Marina with a ship is also interesting.

In this palace, which he owned by inheritance, prof. Gino Bozza (1899-1967), a nationally renowned scientist and researcher, distinguished professor, from 1960 until his death Rector of the Politecnico di Milano, member of the Accademia dei Lincei and the Higher Council of Public Education (for 12 years also a municipal councilor), lived for various periods of the year.