Castel Sant'Angelo

The Castel Sant'Angelo, initially known as the Mausoleum of Hadrian, was a significant, cylindrical fortress located in the Vatican, reachable via the Ponte Sant'Angelo. It was an end point to the Passetto di Borgo, and could be found on the banks of the Tiber.

The Castel was commissioned by the Roman Emperor Hadrian as a tomb for himself and his family. Later, during the Renaissance, the building was used by the Papacy as a fortress and castle.

The Roman Era
The tomb of Hadrian, also called Hadrian's mole, was constructed between 135 and 139 AD. It was originally a decorated cylinder, with a garden top and golden quadriga.

Hadrian's ashes were placed here a year after his death in 138 AD, together with those of his wife, and his first adopted son, who died in the same year. Furthermore, remains of succeeding emperors were placed here as well. Hadrian also built the Ponte Sant'Angelo, formerly known as Pons Aelius.

Destruction
Much of the tomb contents and decoration had been destroyed since the building was changed into a military fortress in 401. The urns and ashes were scattered by looters in Alaric's sacking of Rome in 410, and the original decorations were thrown down upon the attacking Goths when they besieged Rome in 537.

Liberation of Rome
In 1499, the Assassin Ezio Auditore scaled the Castel during his infiltration of the Cappella Sistina, in order to assassinate Pope Alexander VI.

In 1501, upon Ezio's return to Rome, he infiltrated the Castel to rescue Caterina Sforza, and to assassinate Cesare and Rodrigo Borgia. However, though he successfully rescued Caterina, he was unable to kill either Templar leader, after he discovered that Rodrigo thumb|300px|right|A video visual of the Castelwas away from the Castel, and that Cesare had left for Urbino moments after Ezio had arrived.

Soon after this assault, the Castel was guarded by several Papal Guards and French soldiers, courtesy of Cesare's alliance with the French General Octavian de Valois.

In August 1503, Ezio once again infiltrated the Castel through a side gate, with a key he had obtained from Lucrezia Borgia's lover, Pietro. At a window looking into the Castel's Papal apartments, he witnessed the murder of Rodrigo at the hands of Cesare.

At this time, Ezio also found out the location of the Apple of Eden, thanks to Lucrezia.

Trivia

 * Despite being the highest reachable point of any Assassin's Creed game, the flagpole atop the Castel is not a view point.
 * After climbing the flagpole and looking out at the cityscape, clouds appear over the city.
 * One of Subject 16's Rifts is located on the Castel, on the main tower just across from the inner wall.
 * The entire Castel is a restricted area throughout Assassin's Creed: Brotherhood, except during certain memories, such as "The Ezio Auditore Affair."
 * Flylike.png achievement "Fly Like An Eagle" can be earned when Ezio jumps off the pinnacle height of the Castel (the top of the flagpole) with a parachute.
 * Throughout Sequence 5, both entrances to the Castel (the large door near the four Papal guards, and the fence accessing the lower courtyard) are closed, so completion of the "Fly Like An Eagle" achievement is not possible until further game progression.