It was in 530 that the event occurred which gave the building its present name. Pope Gregory the Great was leading a penitential procession to St. Peter’s, in order to offer up prayers for the staying of the great pestilence which followed the inundation of 589; when, as he was crossing the bridge, even while the people were falling dead around him, he looked up at the Mausoleum and saw an angel on its summit, sheathing a bloody sword, while a choir of angels around chaunted with celestial voices, the anthem, since adopted by the church in her vesper service--“_Regina cœli, lætare--quia quem meruisti portare--resurrexit, sicut dixit, Alleluja_.”--To which the earthly voice of the Pope solemnly responded: “_Ora pro nobis Deum, Alleluja_.”[10] In the Tenth Century the fortress was occupied by the infamous Marozia, who, in turn, brought her three husbands (Alberic, Count of Tusculum; Guido, Marquis of Tuscany; and Hugo, King of Italy), thither, to tyrannize with her over Rome. It was within the walls of this building that Alberic, her son by her first husband, waiting upon his royal stepfather at table, threw a bowl of water over him, when Hugo retorted by a blow, which was the signal for an insurrection, the people taking part with Alberic, putting the King to flight, and imprisoning Marozia. Shut up within these walls, Pope John XI. (931–936), son of Marozia by her first husband, ruled under the guidance of his stronger-minded brother Alberic; here, also, Octavian, son of Alberic and grandson of Marozia, succeeded in forcing his election as John XII. (being the first Pope who took a new name), and scandalized Christendom by a life of murder, robbery, adultery and incest. In 974, the Castle was seized by Cencio (Crescenzio Nomentano), the consul, who raised up an anti-pope (Boniface VII.) here, with the determination of destroying the temporal power of the popes and imprisoned and murdered two popes, Benedict VI. (972), and John XIV. (984), within these walls. In 996, another lawful pope, Gregory V., calling in the Emperor Otho to his assistance, took the Castle and beheaded Cencio, though he had promised him life if he would surrender. From this governor the fortress long held the name of Castello de Crescenzio, or Turris Crescentii, by which it is described in mediæval writings. A second Cencio supported another anti-pope, Cadolaus, here in 1063, against Pope Alexander II. A third Cencio imprisoned Gregory VII. here in 1084. From this time the possession of the Castle was a constant point of contest between popes and anti-popes. In 1313, Arlotto degli Stefaneschi, having demolished most of the other towers in the city, arranged the same fate for S. Angelo, but it was saved by cession to the Orsini. It was from hence, on December 15, 1347, that Rienzi fled to Bohemia, at the end of his first period of power, his wife having previously made her escape disguised as a friar.