Oldofredi Castle, in Iseo, stands on a hill in the town's historical centre. Thanks to its strategic location, the castle offers a wonderful view of the lake, especially its towers. Today, the castle serves as the home of the municipal library and a small museum dedicated to the war. The building has a rectangular plan with enormous corner towers, made in natural stone. Since the castle was essentially built for defensive purposes, it was destroyed several times.
The construction of the Oldofredi Castle is believed to date back to the year 1000, commissioned by the Oldofredi family. While the castle was first attacked and set fire by Barbarossa in 1161, other sieges would follow by others such as Frederick II. However, the castle was immediately rebuilt. The town of Iseo, built inside the second expanse of defence walls, grew mainly due to its trade and craft production. Over the centuries Oldofredi Castle even housed a convent and following a period of decay it was restored to its current state. Various rooms of the castles are open to visitors while others are accessible by appointment.