Castel Sant'Angelo is a towering cylindrical castle, initially commissioned by the Roman Emperor Hadrian as a mausoleum for himself and his family. The building was later used by the popes as a fortress and castle, and is now a museum. The castle was once the tallest building in Rome.
The tomb of the Roman emperor Hadrian was erected on the right bank of the Tiber, between 134 and 139 AD. Originally the mausoleum was a decorated cylinder, with a garden top and golden quadriga. Hadrian's ashes were placed here a year after his death in Baiae in 138, together with those of his wife Sabina, and his first adopted son, Lucius Aelius, who also died in 138. Following this, the remains of succeeding emperors were also placed here, the last recorded deposition being Caracalla in 217. The urns containing these ashes were probably placed in what is now known as the Treasury room deep within the building. Hadrian also built the Pons Aelius facing straight onto the mausoleum. It still provides a scenic approach from the center of Rome and the left bank of the Tiber, and is renowned for the Baroque additions of statues of angels holding aloft instruments of the Passion of Christ.
Much of the tomb contents and decorations have been lost since the building's conversion to a military fortress in 401 and its subsequent inclusion in the Aurelian Walls by Flavius Augustus Honorius. The urns and ashes were scattered by Visigoth looters during Alaric's sacking of Rome in 410, and the original decorative bronze and stone statuary were thrown down upon the attacking Goths when they besieged Rome in 537, as recounted by Procopius. An unusual survivor, however, is the capstone of a funerary urn (probably that of Hadrian), which made its way to Saint Peter's Basilica, covered the tomb of Otto II and later was incorporated into a massive Renaissance baptistery.
Legend holds that the Archangel Michael appeared atop the mausoleum, sheathing his sword as a sign of the end of the plague of 590, thus lending the castle its present name.
The popes converted the structure into a castle, beginning in the 14th century; Pope Nicholas III connected the castle to St Peter's Basilica by a covered fortified corridor called the Passetto di Borgo. The fortress was the refuge of Pope Clement VII from the siege of Charles V's soldiers during the Sack of Rome (1527), in which Benvenuto Cellini describes strolling the ramparts and shooting enemy soldiers.
Leo X built a chapel with a Madonna by Raffaello da Montelupo. In 1536 Montelupo also created a marble statue of Saint Michael holding his sword after the 590 plague to surmount the Castel. Later Paul III built a rich apartment, to ensure that in any future siege the pope had an appropriate place to stay.
Montelupo's statue was replaced by a bronze statue of the same subject, executed by the Flemish sculptor Peter Anton von Verschaffelt, in 1753. Verschaffelt's is still in place and Montelupo's can be seen in an open court in the interior of the Castle.
The Papal state also used Sant'Angelo as a prison. Executions were performed in the small inner courtyard. As a prison, it was also the setting for the third act of Giacomo Puccini's 1900 opera Tosca; the eponymous heroine leaps to her death from the Castel's ramparts.
Decommissioned in 1901, the castle is now a museum, the Museo Nazionale di Castel Sant'Angelo.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.