Following the example of Augustus, who erected his mausoleum in the Fields of Mars, a century and a half later, and the emperor Hadrian wanted a monumental tomb to be built for him and for his successors. Mausoleum of Hadrian was built on the right bank of the Tiber, a short distance from the Mausoleum of Augustus.
Its construction began around 130 CE. The tomb consisted of a huge rotunda 21 m high and 64 m in diameter and a square fence covered with precious marbles.
There was an earthen mound on the rotunda covered with cypresses and other trees, and on top of it was a huge gilded bronze quadriga with an emperor’s statue.
Hadrian was buried in the tomb a year after his death in 138 CE because only then was this great undertaking completed by Antoninus Pius. In addition to numerous members of the Emperor’s family, all subsequent emperors were also buried in the mausoleum, including Caracalla, who was the last to be buried here in 217 CE.
To facilitate access to the Mausoleum from the Champ de Mars Emperor Hadrian ordered to build a new bridge over the Tiber, named after the Emperor’s family – Pons Aelius. Preserved intact until the end of the last century, the Aelius Bridge was rebuilt (its two ends were shortened and reworked) and only three middle arcades from 130 and 134 CE remained.
As for the Mausoleum, at the beginning of the 5th century, it was incorporated by Honorius into the lines of Aurelian’s defensive walls in the form of a protruding bastion, and in the 10th century it was converted into a fortress – Castel Sant’Angelo – to defend the Vatican Palaces with which it was connected a special ‘viaduct’.