Fortress of Monselice: the imposing tower, Keep Federiciano, that dominates the top of the Colle della Rocca is a powerful medieval fortification built by Emperor Frederick II of Swabia. It can be reached via a path starting from the steps along Villa Duodo, brings on top of the small mount Monselice. Built on the ruins of an earlier Byzantine castle conquered by the Lombards in 602 AD, for its construction was necessary to demolish the old church of St. Gustina, then rebuilt in the mid-mountain and today also known as the Old Cathedral. It was the year 1239 when, waiting for the decisive battle with the Guelph Marquis Azzo VII d’Este, Frederick II confirmed the city of Monselice as the seat of the imperial court of appeal for the Treviso (Veneto, which corresponds to the Trentino and Friuli) and ordered the rebuilding of the fortress and the construction of a new wall on the hill. The complex is made of a strong base of a truncated pyramid, with hanging blocks of trachyte about 8 feet high, on which rises a square tower originally very hig, but that now seems cut off. After the conquest of Monselice by Carrara family in the fourteenth century, the lords of Padua provided to incorporate the Frederick structure within wider walls, which also served to protect the various villages that sprang up on the nail of the hill and that is still visible in some areas of the historic centre of the city. The arrival of Venetian rule from 1405 led to the sale of the entire fortified complex of Colle della Rocca to some noble families, including the Marcellus and Duodo ones, who here built their holiday residences. However, the defensive function of the hill became necessary for the last time in 1509, when the troops of the Cambrai League at war against Venice, besieged the city damaging the walls and the thirteenth century mastio. In recent times, the archaeological research at the mastio have unearthed a Lombard necropolis, whose rich collection is now on display in the Lombard Antiquarium housed in the Ca’ Marcello library. The fortress holdings include archaeological finds such as potteries, metallic tools and silver objects. The collection objects are provided with exhaustive explanations, and a plastic model showing the defensive structure of the hill through the centuries is displayed inside.