Nicholas III. died in 1280. He had compelled Charles to leave Tuscany, and be satisfied with receiving from Rudolph the investiture of Provence and the kingdom of Naples. To render this agreement more binding, by means of a family alliance, Rudolph gave his daughter in marriage to a grandson of King Charles. But naturally the latter accepted the arrangement most reluctantly, and took every opportunity of secretly exciting the Tuscan Guelphs against the Ghibellines, who were again coming to the front. Also, having learnt by his own experience the serious difference between having the Popes as friends or as foes, he hastened to Orvieto, where the new conclave was sitting, determined to use every means to procure the election of some candidate favouring his views. As usual, he pursued this purpose unhesitatingly and without scruple. Perceiving that the cardinals were temporising, and dreading the consequences of delay, he excited a revolt, during which the populace captured two cardinals of the Orsini house, relations of the deceased Pope, and decidedly opposed to the Angevin interests. After this event the election took place, and on February 22, 1281, Martin IV. was proclaimed. The new pontiff was French, and being very friendly to Charles, immediately undertook to forward his policy and support the Guelphs. But the general conditions of Italy were much changed, and therefore the king's triumph at Orvieto failed to prevent the consequences entailed by his cruelty in Naples, and by the policy of Nicholas III. from producing their natural effect. The latter's agreement with Rudolph was ratified by the new Pope, who counselled the cities of Italy to accord a hearty welcome to the emperor's daughter, when she came as the bride of the king's nephew. Even Florence was obliged to give the princess an honourable reception, although she was accompanied by an Imperial vicar, who, as usual, abode at San Miniato, in order to attempt to resuscitate the rights of the Empire in Tuscany. But a far graver change occurred in March, 1282, when the Sicilians, wearied of misgovernment, at last snatched up the gauntlet thrown by Conradin to the people, and with the sanguinary revolt of the Vespers began the long and glorious war that was to free Sicily for ever from the Angevin yoke. In order to keep faith with the Guelph party and avoid unnecessarily irritating the Pope or the king, the Florentines sent five hundred horse to the latter's aid; and this contingent, commanded by Count Guido di Battifolle of the Guidi house, and bearing the banner of Florence, took part in the siege of Messina. But the revolution was everywhere triumphant; the Florentines shared in the general defeat, and had to return, leaving their flag in the enemy's hands. The island was inevitably lost to the French.