Part two.
Hadrian's Mausoleum had the shape of a large circular tower and was therefore transformed into a fortress, similar to the Mausoleum of Caecilia Metella on the ancient Appian Way, which was included in the fortifications of the Castrum Caetani.
The Mausoleum took the name Castel Sant'Angelo only in 590 AD, after the legendary apparition of the Archangel Michael to Pope Saint Gregory the Great, announcing the end of the terrible plague that had decimated the population.
In 270 AD, Emperor Aurelian built new walls to defend Rome from increasingly frequent barbarian attacks. At the end of the 14th century, Pope Boniface IX dug a moat around the circular body of the Mausoleum and walled up the original entrance, opening a higher one, protected by a drawbridge. Thus began its transformation into the impregnable fortress that would withstand countless sieges over the centuries.
In 401 AD, the emperors Honorius and Arcadius reinforced the Aurelian Walls and connected them to the Mausoleum, because its tower-like shape and height made it a strategic observation point. It thus became the city's most important defensive stronghold on the right bank of the Tiber, from which one of the main access points to the city, the Pons Aelius, was controlled.
In 410 and again in 455 AD, the Mausoleum withstood the first sieges by the Visigoths and Vandals, who failed to capture it but instead sacked the entire city. Shortly thereafter, the Leonine Walls were built to protect also St. Peter's Basilica.
In 537 AD Rome was again attacked by the Goths led by Vitiges, who attempted to conquer the Mausoleum by scaling its walls with ropes and ladders. The Romans barricaded themselves inside it under the leadership of General Belisarius, who realized that ballistae could not be used for defense because they could not hurl their projectiles downward, only forward.
The situation was desperate, but desperate times call for desperate measures. Procopius of Caesarea described the siege a few years later, in 550 AD, in his De Bello Gotico (Gothic War). He wrote that Belisarius decided to break into pieces the ancient statues decorating the Mausoleum and use the marble fragments as projectiles, throwing them at the enemies, who were scared and fled.
It was the beginning of the end: from that moment on, the Mausoleum was robbed of all its precious marbles; the travertine, for example, was sold by the City and used to pave Rome's squares.
At the end of the 15th century, when Pope Alexander VI Borgia had new moats dug around Castel Sant'Angelo, several fragments of sculptures were discovered, confirming the accuracy of Procopius's account. Other fragments were found in the late 19th century, during the construction of the embankments of the Lungotevere.
In 1527, the Landsknechts (German mercenaries) attacked the castle, but even they failed to capture the Castle. The pope had taken refuge there with several thousand people, walking along the Passetto, an elevated pedestrian walkway that connected St. Peter's Basilica to the Castle and was used as an escape route on several other occasions.
The sack of Rome lasted seven months, during which the German mercenaries burned documents, destroyed works of art, and massacred the population with every form of violence. And after months, they finally managed to capture the Castle with the most classic and effective of siege weapons: starvation. Having run out of food, Pope Clement VII was forced to surrender.
After him, Pope Paul III had to humble himself in 1536 by welcoming Charles V of Spain as the victor in a city reduced to poverty, preparing papier-mâché decorations to give it a semblance of dignity.
Despite those tragic events, after the medieval devastation the Castle was reborn because since the 15th century it was transformed into an official residence by the great popes of the Renaissance and Baroque periods.
They called upon some of the greatest artists of their time, including Raphael, Michelangelo, Antonio da Sangallo and Baldassarre Peruzzi, to design and decorate the papal apartments. They added new floors, loggias, and rooms, and enclosed the ancient remains within a marvelous Renaissance shell, which deeply altered its appearance.
A monumental access was created with a drawbridge, and pope Alexander VI Borgia even built hanging gardens with pavilions frescoed by Pinturicchio and a large tower to defend the bridge.
The second life of Castel Sant'Angelo is therefore closely linked to the history of Italian and Renaissance art, reflecting the continuity of power and its symbols between the Roman Empire and the Church, between Hadrian and the Archangel Michael.
This and many other fascinating stories of the second Renaissance life of the Mausoleum-turned-Castle are recounted in detail in our book, «Castel Sant'Angelo. Mausoleum of Hadrian. Architecture & Light» which traces its two-thousand-year history, closely linked to that of the city of Rome.
It is a true guide to visiting it with new eyes, understanding its hidden symbolic meaning.
The book is on sale in the Bookshop of the National Museum of Castel Sant'Angelo, also in English edition.