During the High Medieval, Monselice was a comitatus, with Este and Padua under its government. Monselice fell into the hands of Ezzelino da Romano, who ceded it to the Holy Roman Emperor, Frederic II of Swabia. Ezzelino had earlier married the emperor's daughter Selvaggia. Tradition has it that it was the Emperor who had the rocca (stronghold) built, at the summit of Monselice, on a previous Byzantine fortification. When Ezzelino fell, Monselice went to the Commune of Padua, but in 1317 it was sub}ugated by Cangrande della Scala, of Verona. In 1338, after a devastating siege imposed by Ubertino, it returned to Padua and the history of the signoria. The Castello is both complex and fascinating, with components dating to various eras. It includes Romanic components, modified from pre-existing Lombard stuctures, consisting of a house and small castle. There is also the so-called 'Ezzelino cube', dating to the mid-13th century, which actually can not be attributed to Ezzelino, with full confidence. Some rooms were constructed by the Marcello nobles in the second half of the 15th century. There is also a library building from the 1600s, and an 18th century church attributed to the architect Andrea Tirali. Prints from the 1300s show Monselice with the five concentric walls that Ubertino erected for its protection. The Carraresi lived in the Romanic part of the Castello and in the part said to date from Ezzelino. They partitioned the long Romanic room with its typical cylindrical fireplace and chimney, which they then used for opening fireplaces into the various new rooms. Jacopino III lived in the castle in a state of imprisonment, as punishment for his conspiracy against Francesco I, and eventually died here. The so-called 'Council Hall' shows a decorative frieze with motif of the Carrarese cart. Two other fireplaces are found in the Ezzelino 'cube': one is in the armoury and the last one is in one of the three rooms created by the Carraresi on the third floor, all of which are painted in red and white heraldic checks.