The arts received a new shock from the sack of Rome, 1527, and the expulsion of the Medici from Florence, at which crisis the Signoria conferred on Michael Angelo, who was a warm Republican,[73] the superintendence of the fortifications and the defence of Monte Miniato, on which the safety of the city depended. Meanwhile what time he could save from his public trust, he secretly[74] employed to finish or advance the symbolic and monumental statues of S. Lorenzo, and from the cartoon to paint in distemper a Leda for the Duke of Ferrara. Finding, however, that no defence could save the city, he saved himself by the secret paths of S. Miniato, and escaped to Venice, 1529; from whence he only returned to find the dominion of the Medici once more established, himself pardoned, again employed by Clemente at S. Lorenzo, and soon after sent for to Rome on a plan of painting two central frescoes, the Last Judgement and the Fall of Lucifer, for the Sistine Chapel,--long favourite ideas of the artist,[75] but with the works at Florence for that time checked by the death of Clemente, 1534. He now with redoubled ardour applied to the monument of Giulio, urged by his devotion to the house of De Rovere, the considerable pecuniary advance he had received, and the threats of the executors and the Duke of Urbino; but the accession of Paul III. again frustrated his exertions: the Pontiff resolved to have the exclusive boast of powers he had so long admired, interposed his authority, and obliged the executors and agents of the Duke to give up the original circumambient plan, and content themselves with the storied front which exists now.