In the 12th century the Mausoleum suffered the fate of all the other great buildings of Rome. It became a castle of the Colonna family, and bore the name Augusta. The mound of earth was then probably removed, and a stone or brick tower built in its place. Previously to this, the statue of Augustus, with the bronze decorations of the Pantheon and Forum of Trajan, had probably been carried to Syracuse by Constans, and thence to Alexandria by the Saracens. The building might, however, still, like the tomb of Hadrian, have long defied the attacks of time, had not the Romans themselves, in the commotions of 1167, demolished the Colonna Castle, and with it the greater part of the walls upon which it was built. Two hundred years later, the body of the last of the Tribunes, Cola di Rienzi, was burned by the Jews before the Mausoleum.[103] At that time the spot was called Campo d’Austa from the ancient site of the Ustrina. The interior chambers seem to have been entirely demolished in the 15th century, and only the exterior wall left. Poggio, the Florentine, describes the building as used in his time (1440) for a vineyard, and before that date its shape was completely changed by the falling in of the vaulting of the interior, so that it presented the appearance of an amphitheatre instead of a lofty conical building. In Donatis’ book (1638), it is represented as a funnel-shaped ruin with a garden on the sloping sides of the interior. Much information might doubtless be gained by well-directed excavations, which have apparently never been undertaken on account of the present occupation of the ruin as a circus in winter and a theatre (the Teatro Correa) in summer. [Sidenote: Muro Torto.] Beyond the Porta del Popolo on the edge of the Pincian hill, there is a very ancient piece of wall, faced in the style called opus reticulatum, which is made of small diamond-shaped blocks of tufa set in the surface of a mass of concrete. These blocks are driven into the concrete before the lime has dried and set. This ruin, which is called the Muro Torto, is often spoken of as having been a part of the house of Sylla but I do not know upon what authority. It may have formed a part of the substructions of some of the private buildings on the Pincian, previous to the time of Aurelian, who incorporated it in his wall. Near the angle of the wall where it turns sharply to the south is a point at which the brickwork leans in great masses considerably out of the perpendicular, whence the name of Muro Torto. Procopius speaks of this as having been in the same state long before his time, and calls it the broken wall. [Sidenote: Pons Ælius.]