The Mausoleum of Hadrian, usually known as the Castel Sant'Angelo, is a towering cylindrical building in Rome, initially commissioned by the Roman Emperor Hadrian as a mausoleum for himself and his family. The building, located in the rione of Borgo, spent over a thousand years as a fortress and castle, and is now a museum.The tomb of the Roman emperor Hadrian was erected on the right bank of the Tiber, between 135 and 139. 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 Ponte Sant'Angelo facing straight onto the mausoleum it still provides a scenic approach from the center of Rome and the right bank of the Tiber, and is renowned for the Baroque additions of statuary of angels holding aloft elements of the Passion of Christ. Much of the tomb contents and decoration has been lost since the building's conversion into a military fortress in 401 and inclusion by Flavius Augustus Honorius in the Aurelian Walls.