CASTEL SANT'ANGELO. - In Rome, on the right bank of the Tiber, facing the Campus Martius, Hadrian had the new mausoleum built for the imperial family, since that of Augustus was by then full of tombs. Construction began around 130 A.D. and was completed by Antoninus Pius in 139. The mausoleum consisted of two parts: an inner cylindrical body (diameter 64 m., height 21 m.) and a large square outer plinth (89 m. long, 15 m. high), connected by a series of walls arranged in a radial pattern. From the mass rose a tall podium supporting, it seems, the quadriga of the Sun or a colossal statue of the emperor. Modern studies (G. Lugli, I monumenti antichi, III, Rome 1938, p. 707) regard as false the sixteenth-century hypothesis, also accepted in the last century, that the crowning element was a pine cone. The central building was entered, as today, through a vestibule preceded by a corridor. Above the burial chamber rests another square chamber, and above this a very tall circular chamber. Perhaps a fourth existed above it, within the podium.
After receiving the remains of the emperors down to Caracalla, under Honorius (395) the mausoleum began to form part of the defenses of the City. The fortification works consisted chiefly in the construction of a high wall joining the mass to the right bank of the river; a wall defended by 6 towers, 163 merlons, 13 windows for ballistae and 18 for archers.
On the reconstruction of these fortification works modern archaeologists disagree. According to Lanciani (Forma Urbis, Rome 1893-1901, pls. VII and XIV), there existed on the front a large projecting structure with 6 towers; Richmond (The City Wall of Imperial Rome, Oxford 1930, fig. 6) reconstructs instead only two towers at the head of the bridge, and two parallel walls between the bridge itself and the entrance of the mausoleum. This reconstruction, however, excludes 4 of the 6 towers mentioned by the regional catalogues. The new defensive function of the mausoleum was put to the test by the first descent of the barbarians: that of the Goths of Alaric (410). Then it withstood the assault of the Goths of Vitiges (537), of Narses and of Totila (548).
Probably to the 10th century dates the transformation into a castle, through the work of Alberic and Marozia; from then on the monument played a very important part in the history of Rome and of the papacy.
In this time it witnessed the assassinations of the popes John X (928) and Benedict III (974), and the imprisonment of John XIV (985). Then it became the property of the Crescenzi (Castelum Crescentii it is still called in the Mirabilia of 1100 and 1200). But already from the 12th century the monument begins to take on the current name of C. S. A., attesting to the cult of the Archangel; a cult expressed first by a chapel at the summit of the monument, later replaced by a statue of the Archangel. Popular tradition has linked this cult to the story according to which in 590, following the prayers of St. Gregory in-
Probably to the 10th century dates the transformation into a castle, through the work of Alberic and Marozia; from then on the monument played a very important part in the history of Rome and of the papacy.
invoking the cessation of a terrible plague, an angel is said to have alighted on the top of the mausoleum, in the act of sheathing his sword as a sign of the granted divine grace.
In 1277 the C. passed into the power of the papacy, of which it became the stronghold, and it was joined to the Vatican by the "passetto" or "corridore di Borgo," built by Nicholas III.
A first important restoration, which earned the C. the appellation of "marvelous fabric" recorded in the chronicles of the Jubilee of 1400, took place under Boniface IX (1389-1404), through the work of Niccolò di Pietro Lamberti d'Arezzo, to repair the immense damage caused by the people after the victory of Urban VI over the antipope Clement VII (1379).
There followed the works of Martin V (1417-31) and those of Eugene IV (1431-47), then the very important ones of Nicholas V (1447-55). The latter had two small chapels erected at the entrance of the Pons Aelius; in the mausoleum he had three great towers added at the corners of the base and had the central great tower and the Roman wall of the quadrangular base strengthened; on the summit of the "maschio" (that is, the central great tower) he had a statue of the archangel Gabriel placed, in memory of the ancient miraculous apparition.
Even more remarkable were the works carried out by Antonio da Sangallo the Elder (the drawings are in the Vatican and at the Escorial in Madrid) for Alexander VI (1492-1503): a great tower was built in front of the entrance; a perimeter moat was dug with a water intake from the Tiber; the central cylindrical body was raised, the tower above it (called "dei Crescenzi") damaged by lightning in 1497 was rebuilt; the towers of Nicholas V were reinforced with a base on an octagonal plan and their battlements were restored; in the C. storerooms were created (the oil-cellars and the silos) and a large cistern. After these works the C. became a heavily fortified stronghold, defended by 200 cannon. These fundamental changes in the C. are documented by various views: the detail of a fresco by Bicci di Lorenzo (cloister of S. Bernardo, at Arezzo) which shows the mass before the works of Nicholas V; a detail of Mantegna's decoration in the room of the Spouses of the palace of Mantua takes account of the works of Nicholas V; to commemorate the works of Alexander VI a medal was struck. Another notable record of the mass of the C. at the end of the 15th century is in the painting by Carpaccio, depicting the meeting of St. Ursula and her spouse with Pope Cyriacus.
During the pontificate of Julius II (1503-13), the works in C. S. A. were directed above all to embellishment: and toward the bridge the loggia attributed to Antonio da Sangallo the Elder was opened. Leo X (1513-21) followed, who had the chapel built on the level of the courtyard of honor which was dedicated to the Medici saints Cosmas and Damian, perhaps executed on a design by Michelangelo, and began the construction of a bath.
Clement VII (1523-34) continued this work, having this room and two ground-floor rooms decorated. Giulio Romano and Giovanni da Udine worked there. He endured there in 1527, on the occasion of the sack, the siege that ended with the surrender and with his flight. Cellini, who was present, described some scenes of that memorable event. He returned there under Paul III as a prisoner. This Pontiff had an apartment built there, of which the following form part: the room of Apollo, the Pauline Hall, the room of Perseus, that of Cupid and Psyche, the corridor between the two aforementioned rooms, the room of the Hadrianeum, the room of the festoons, the Cagliostra (so called for having hosted, at the end of the 18th century, according to tradition, Cagliostro), the cabinet of the Dauphin and of the Salamander, and that of the Stork (so called from the depiction of the emblems of Paul III). At this time the angel of Nicholas V, struck by lightning, was also replaced with a marble angel (the work of Guglielmo della Porta). Moreover, in the plan for strengthening the defenses of Rome, in view of the Turkish and Barbary danger, Paul III gave great importance to the consolidation of the C. The works studied by Michelangelo, Antonio da Sangallo, Bartolomeo de' Rocchi, were nevertheless not carried out.
A third outer pentagonal enceinte was built under Paul IV (1555-59) by Camillo and Latino Orsini, but in a wholly provisional manner (it is documented in 1557 by the plans of Rome by Paciotto and Beatrizet), to resist the invasion of the troops of the duke of Alba in the service of Spain, which had entered the war against the Pope; the enceinte was swept away by a flood (Sept. 14, 1557); following its course, Pius IV in 1561 had a new masonry enceinte built by Francesco Laparelli da Cortona, Latino Orsini, Galeazzo Alessi, and other military architects. Under Paul IV the C. had also had its entrance portal, the work of Salvestro Peruzzi (1556). Demolished in 1892 for the works of the lungotevere, it was rebuilt in 1933, between the bastions of S. Giovanni and of S. Luca.
The fortification work of Pius IV was continued, between the C. and the Borgo, by Pius V (1566-72). He extended the outer moat as far as the Tiber and near the river erected a half-bastion which was later called that of S. Spirito.
Other important works were carried out under Urban VIII, between 1626-30, with the architects Vincenzo della Greca, Gian Battista Mola and, later, also Bernini. The most important works consist in having created casemates, galleries and emergency doors in the bastions; erected barracks, storerooms and powder magazines between the second and third enceinte; enlarged and reinforced the bastions of Alexander VI, which from then on were distinguished by the names of the Evangelists; the bastions of the pentagonal enceinte were named: of the Savior, of S. Maria, of S. Paul, of S. Peter, of S. Spirito.
After Urban VIII, the access bridge was instead arranged, through the work of Bernini, under Clement IX (1667). The C., having by now lost its character as a fortress, was destined only as barracks and prison.
Benedict XIV (1740-58) had the angel of della Porta replaced with the bronze one, which is still there today, by P. Verschaffelt.
Under Pius IX (1865) the bastion of S. Spirito was demolished. With 1870 the C. remained a barracks; however in 1886, through the impulse of Mariano Borgatti, to whose care the monument was entrusted, excavations and restoration works were undertaken which continued for forty years, thus resuming the earlier excavations of 1825 which had brought to light the helical ramp and the burial chamber; a national monument, the C. became the seat of a military museum.
In 1934, on a project by A. Spaccarelli, the isolation of the mass was carried out, which resumed, at least in part, its 16th-century appearance. - See Pl. LVII.
