Castel Sant’Angelo National Museum is housed in the Sant’Angelo Castle. It was built in 135-139 a.C., to fulfill the wish of Emperors Adriano and, then, Antonino Pio. Nowadays the castle looks like a fortification from which a gigantic, monumental circular tower emerges. At the beginning it was conceived as a mausoleum for Emperor Adriano’s dynasty.Under the reign of Emperor Aureliano, the castle underwent some changes: four bastions and new walls were added and the whole complex was incorporated in a strategic fortification for the defence of Rome. In the XI century Pope Benedetto IX ordered the “cylindric body” to be raised: on top of it, Pope Giulio II (1503-13) placed the apartments of the Pope and the bronze statue of the Angel sheathing his sword. The angel, represented by the statue, appeared to Pope Gregorio Magno in 590: from the top of the castle, it dominates the whole city of Rome.The castle houses the National Museum of Castel Sant’Angelo. In the richly adorned apartments of the Pope, paintings, collections of ancient arms, documents and furnishings are displayed. The visit to the museum includes the apartments of the Pope and the Renaissance cells for prisoners.