After the burial of M. Aurelius the tomb was closed until the sack of Rome by Alaric in A.D. 410, when this barbarian’s soldiers probably broke it open in search of treasure, and scattered the ashes of the Antonines to the winds. From this time for a hundred years the tomb was turned into a fortress, the possession of which became the object of many struggles in the wars of the Goths under Vitiges A.D. 537 and Totilas who was killed A.D. 552. From the end of the sixth century, when Gregory the Great saw on its summit a vision of St. Michael sheathing his sword in token that the prayers of the Romans for preservation from the plague were heard, the Mausoleum of Hadrian was considered as a consecrated building under the name of S. Angelus inter nubes, usque ad cælos, or inter cælos, until it was seized in A.D. 923 by Alberic, Count of Tusculum and the infamous Marozia, and again became the scene of the fierce struggles of those miserable ages between popes, emperors, and reckless adventurers.[107] The last injuries appear to have been inflicted upon the building in the contest between the French Pope Clemens VII. and the Italian Pope Urban VIII. The exterior was then finally dismantled and stripped. Partial additions and restorations soon began to take place. Boniface IX., in the beginning of the fifteenth century, erected new battlements and fortifications on and around it, and since his time it has remained in the possession of the Papal Government. The strange medley of Papal reception rooms, dungeons, and military magazines which now encumbers the top was chiefly built by Paul III. The corridor connecting it with the Vatican dates from the time of Alexander Borgia (A.D. 1494), and the bronze statue of St. Michael on the summit, which replaced an older marble statue, from the reign of Benedict XIV.[108] CHAPTER VII. THE QUIRINAL HILL--BATHS OF DIOCLETIAN--AGGER OF SERVIUS--CASTRA PRÆTORIA. [Sidenote: Baths of Diocletian.]