Built around 123 A.D. as a tomb for Emperor Hadrian and his family, and later became the family dynastic tomb for the Antonini family (with the emperors Aurelian and Honorius). Its imposing mass was included in the walls of Rome and turned into a kind of fortress for the defense of the city, and therefore called castellum. In the early Middle Ages, the legendary vision of the Archangel Michael deposing the sword as a proof of the end of the plague gave it its new name – Sant'Angelo.
Its proximity to Saint Peter's Basilica, plus its strategic position at the north entrance of the city and its closed and imposing body, made Castel Sant'Angelo center of political interests. The castle’s fate was sealed in 1367 when Pope Urban V sought the keys of the castle as a condition for the return of the papal Curia to Rome.
Since then, many architectonic interventions have added news sections. Some adapted the building to new defense requirements with the construction of bastions and the pentagonal wall. Others gave comfort to the Curia, giving the appearance of a true royal residence for pope Paolo III Farnese (1534-1549).
In more recent times the castle was used as a political prison, and renamed Forte Sant'Angelo; in 1925 it was transformed into the National Museum.
The museum was officially created in 1911 for the Universal Exhibition. In 1926 it became a Sculpture and Minor Arts Museum. At the same time, some works already purchased by the castle were transferred to Palazzo Venezia that hosted the Museum of Medieval History and the History of Rome. The important collection of paintings and furniture that decorate the historic rooms arrived at a different time.
In 1916, Mario Menotti, Roman collector, donated a collection of old paintings and decorations to the Hall of Love and Psyche (including the famous San Girolamo by Lorenzo Lotto) to reconstruct a Renaissance papal chamber. In 1928, Alessandro and Vittoria Contini Bonacosi made a similar donation to decorate the other rooms of the papal apartments.
The establishment and design of the museum are credited to Mariano Borgatti, first director of the castle. The military administration brought a rich collection of ancient and modern weapons (currently mostly in storage) and historical military antiques, almost all taken to the Vittoriano. The military footprint was kept in the museum until the 1970s, when it took a new direction with greater attention to decorations and frescoes, which were completely restored between 1979 and 1981. A new collection of ceramics from the 15th to the 18th centuries, and an interesting core of medieval and modern sculptures were also added to the museum's collections.
The museum was then enriched with a space dedicated to the history of Castel Sant'Angelo. Located in the halls of Alessandro VI, the exhibition includes a series of engravings, lithographs and reconstruction drawings to illustrate the various historical phases that have changed and influenced the monument in the course of its long history. Divided into four sections, the castle's history is illustrated by vintage lithographs, panoramas, and model reconstructions of the monument, as suggested by the imagination of artists and architects of the Renaissance, from its construction to the 19th century.
From funerary monument to fortified outpost, from dark and terrible dungeon and prison during the Risorgimento to splendid Renaissance residence and now to a museum, Castel Sant'Angelo with its solemn, strong walls and sumptuously frescoed rooms embodies the history of the Eternal City, inextricably linking past and present.