Castel Sant'Angelo historical timeline

Last updated on October 5, 2026

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A tomb that became a wall, then a castle, then a strongroom, a courthouse and a prison — and finally a museum.

Chronology

134 or 135 AD — Hadrian, wanting a funerary mausoleum for himself and his family, turns to the architect Demetriano, with in mind a tomb in the style of the Mausoleum of Augustus but markedly larger. Turismo Roma dates the start to 135; the reference work gives the build as 134 to 139. Structural impact: a cubic base in Luni marble carrying a drum. What you see today: the lower half of the castle.
139 — the mausoleum is finished by Antoninus Pius, a year after Hadrian's death. Structural impact: a garden top and a bronze quadriga carrying Hadrian in triumph. What you see today: neither — but the shape they stood on.
138–217 — Hadrian's ashes are placed here a year after his death at Baiae, with his wife Sabina and his adopted son Lucius Aelius; then Antoninus Pius and Faustina the Elder, and the emperors Commodus, Marcus Aurelius, Septimius Severus, Geta and Caracalla. The last recorded deposition is Caracalla in 217. Structural impact: none. What you see today: the chamber, empty.
401 or 403 — the building is converted to a military fortress and included in the Aurelian Walls by Honorius, losing its original function and beginning to be called castellum. The reference work dates this to 401, Turismo Roma to 403. Structural impact: a tomb becomes a bastion. What you see today: why a mausoleum has walls.
410 — the urns and ashes are scattered by Visigoth looters during Alaric's sacking of Rome. Structural impact: none to the fabric. What you see today: an imperial tomb with no emperors in it.
537 — the original decorative bronze and stone statuary is thrown down upon the attacking Goths besieging Rome, as recounted by Procopius. Structural impact: the decoration is used as ammunition. What you see today: bare brick where sculpture was.
c. 590 — during a procession to avert a plague decimating the city, Pope Gregory I has a vision of the archangel Michael sheathing his sword atop the Mole. The plague ends; a church to Saint Michael follows, and later a statue of the angel putting away his sword. Structural impact: a church and a statue on the summit. What you see today: the name, and the angel.
13th century — Niccolò III Orsini has the Passetto built between the Vatican and the castle. Structural impact: a covered wall-top corridor. What you see today: it, running above the Borgo.
1365 — after disputes over ownership, the castle is ceded by the Orsini to the Church. Structural impact: none immediately. What you see today: the reason everything above the Roman drum is papal.
1494 — the Passetto eases the flight of Pope Alexander VI, Rodrigo Borgia, from the Vatican to the far safer castle during the invasion of Rome by the militias of Charles VIII of France. Structural impact: none. What you see today: a corridor with a record.
Around 1500 — Alexander VI Borgia has Antonio da Sangallo the Elder turn the castle into a true military stronghold, building the four pentagonal bastions and the moat, and embellishes it with gardens and fountains and a new apartment frescoed by Pinturicchio. Structural impact: the outer defences you walk through. What you see today: the bastions, the moat, and painted rooms.
1527 — the Passetto carries Pope Clement VII, Giulio de' Medici, to safety during the Sack of Rome by the landsknechts of Charles V. Structural impact: none. What you see today: the second time it worked.
16th century — other popes turn rooms into reception rooms and private chambers, among them the Sala di Apollo, frescoed with grotesques by Perin del Vaga, who took his inspiration from the rooms of the Domus Aurea decorated with cupids, griffins, satyrs and tritons. Structural impact: a fortress acquires state rooms. What you see today: the painted interiors.
From the mid-14th century — the monument is used as a prison, a use kept at least until the early 1900s. Besides cells reserved for prisoners of note — Beatrice Cenci, Benvenuto Cellini, Cagliostro, Giordano Bruno — there is the Sammalò, into which the condemned was lowered from above with barely the space to crouch. Structural impact: cells cut into the mass. What you see today: them.
1667–1669 — Pope Clement IX has ten marble angels placed along the Pons Aelius, which from then is called Ponte Sant'Angelo. They are by Gian Lorenzo Bernini and his workshop; the first two, carved by Bernini himself, are today in the Church of Sant'Andrea delle Fratte. Structural impact: the approach becomes a sculpture gallery. What you see today: ten angels, eight of them workshop copies of a sort.
1933–1934 — the castle is completely restored: the moats and bastions are reinstated and the area outside the fortifications is laid out as a garden. Structural impact: the defences are reconstructed. What you see today: the moat as a lawn.
1925 — the ancient Mausoleum of Hadrian is transformed into a museum. Structural impact: none. What you see today: its present use, and its eighth.

Verified against Turismo Roma, October 2026.

Sources & verification Covers the sourced claims on this page.

Checked against Turismo Roma — Turismo Roma records that the history of Castel Sant'Angelo begins in 135 AD at the will of the emperor Hadrian, who wanting a funerary mausoleum for himself and his family turned to the architect Demetriano, with in mind a monumental tomb in the style of the Mausoleum of Augustus but of markedly greater dimensions, and that it was finished in 139 by Antoninus Pius, a year after Hadrian's death — where the reference work gives the building as erected between 134 and 139, Turismo Roma records that Hadrian's wife Vibia Sabina, the emperor Antoninus Pius and his wife Faustina the Elder, and the emperors Commodus, Marcus Aurelius, Septimius Severus, Geta and Caracalla also found burial in the mausoleum, and that on its summit stood a bronze quadriga carrying the emperor Hadrian in triumph, Turismo Roma records that in 403 AD, perhaps by work of the emperor Honorius, the building was included in a bastion of the Aurelian walls, entering the city's defensive system and losing its original function, and that this was also the period in which it began to be called castellum — where the reference work dates the conversion to a military fortress to 401, Turismo Roma records that around 590, by tradition, the Mausoleum of Hadrian took its present name during a procession organised to avert the grave plague that had struck the city and was decimating its population, when Pope Gregory I had a vision of the archangel Michael sheathing his sword at the top of the Mole Adriana, an event interpreted as a sign from heaven announcing the end of the plague, and that in thanks the pope had a church dedicated to Saint Michael erected and a statue was later placed showing the angel in the act of putting away his sword, Turismo Roma records that after various vicissitudes and disputes over ownership, and after being used as a prison — a use it kept at least until the early 1900s — the castle was ceded by the Orsini to the Church in 1365, and that thanks to its massive fortified structure the popes began to use Castel Sant'Angelo as a refuge, as the seat of the Vatican Archive, as a kind of vault for the Treasure of the Church, as a tribunal and as a prison, Turismo Roma records that Niccolò III Orsini had the famous and most useful Passetto built, which in 1494 eased the flight from the Vatican to the far safer castle of Pope Alexander VI, Rodrigo Borgia, during the invasion of Rome by the militias of Charles VIII of France, and in 1527 that of Pope Clement VII, Giulio de' Medici, during the Sack of Rome carried out by the landsknechts of Charles V, Turismo Roma records that one of the most substantial of the castle's later transformations was carried out by order of Pope Alexander VI Borgia by Antonio da Sangallo the Elder, who made it a true military stronghold and built the four pentagonal bastions and the moat, and that the pope also embellished the castle with gardens and fountains and had a new apartment fitted out, frescoed by Pinturicchio, Turismo Roma records that Castel Sant'Angelo was completely restored between 1933 and 1934, years in which the moats and bastions were reinstated and the area outside the fortifications was laid out as a garden, Turismo Roma records that the monument was used as a prison from the middle of the 14th century and that besides frightful cells such as the one called Sammalò or San Marocco, into which the condemned was lowered from above and had barely the space to crouch, being unable to stand or to lie down, the castle also held cells reserved for prisoners of note, among them Beatrice Cenci, Benvenuto Cellini, Cagliostro and Giordano Bruno, Turismo Roma records that in 1925 the ancient Mausoleum of Hadrian was transformed into a museum (October 2026).
Checked against Wikipedia — The tomb of the emperor Hadrian, also called Hadrian's mole, 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, and Hadrian's ashes were placed here a year after his death at Baiae in 138, together with those of his wife Sabina and his first adopted son Lucius Aelius, with the remains of succeeding emperors also put here, the last recorded deposition being Caracalla in 217, The urns containing the imperial ashes were probably placed in what is now known as the Treasury Room, deep within the building, and Hadrian also built the Pons Aelius facing straight onto the mausoleum, which still provides a scenic approach from the centre of Rome and is renowned for the Baroque additions of statues of angels holding aloft instruments of the Passion of Christ, Much of the tomb's 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 Honorius Augustus — a date that differs from the 403 given by Turismo Roma — and the urns and ashes were scattered by Visigoth looters during Alaric's sacking of Rome in 410, The original decorative bronze and stone statuary of the mausoleum was thrown down upon the attacking Goths when they besieged Rome in 537, as recounted by Procopius, An unusual survivor from the mausoleum is the capstone of a funerary urn, probably Hadrian's, which made its way to Saint Peter's Basilica, covered the tomb of Otto II and was later incorporated into a massive Renaissance baptistery, while Giorgio Vasari records in the 16th century that stone columns were taken from the tomb of Hadrian, then the castle of Sant'Angelo, to ennoble and decorate Saint Peter's, 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 (October 2026).

Castel Sant'Angelo historical timeline

Chronology

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