At the Diet at Ratisbon, there were present ambassadors from France, empowered to adjust the differences which seemed to menace a war in Italy between the Emperor and their sovereign. Vincent, Duke of Mantua and Montferrat, dying without issue, his next relation, Charles, Duke of Nevers, had taken possession of this inheritance, without doing homage to the Emperor as liege lord of the principality. Encouraged by the support of France and Venice, he refused to surrender these territories into the hands of the imperial commissioners, until his title to them should be decided. On the other hand, Ferdinand had taken up arms at the instigation of the Spaniards, to whom, as possessors of Milan, the near neighbourhood of a vassal of France was peculiarly alarming, and who welcomed this prospect of making, with the assistance of the Emperor, additional conquests in Italy. In spite of all the exertions of Pope Urban VIII. to avert a war in that country, Ferdinand marched a German army across the Alps, and threw the Italian states into a general consternation. His arms had been successful throughout Germany, and exaggerated fears revived the olden apprehension of Austria's projects of universal monarchy. All the horrors of the German war now spread like a deluge over those favoured countries which the Po waters; Mantua was taken by storm, and the surrounding districts given up to the ravages of a lawless soldiery. The curse of Italy was thus added to the maledictions upon the Emperor which resounded through Germany; and even in the Roman Conclave, silent prayers were offered for the success of the Protestant arms. Alarmed by the universal hatred which this Italian campaign had drawn upon him, and wearied out by the urgent remonstrances of the Electors, who zealously supported the application of the French ambassador, the Emperor promised the investiture to the new Duke of Mantua.