The emperor made no mistake in the choice of his ambassador, of whose turn of thinking he doubtless was not ignorant, but on the exercise of whose talents he knew he could rely. He considered him the fittest person that could be selected to go to the council of Trent, and recommend, by an elegant manner, the truths he wished to be told to the assembled fathers in the name of the Spanish nation. This commission Mendoza executed to the satisfaction of the emperor. The speech which he delivered before the council in 1545 was highly admired, and Charles was convinced that it was impossible to confide the affairs of Italy to better hands. In the year 1547, Mendoza appeared at the papal court, then the centre of all political intrigues, as imperial ambassador, and invested with powers which rendered him the terror of the French party in Italy. The emperor at the same time appointed him captain-general and governor of Sienna, and other strong places in Tuscany. He was ordered to humble the pope, Paul III. even in his own court; and to repress, by force, the movements of the restless Florentines, who still hoped, under the protection of France, to shake off the yoke of the Medicis. A man of less firmness of character would have been totally unfit for such a task; but the terrible energy with which Mendoza performed it, exasperated in the highest degree the opposite party, and more particularly the Florentines. The repeated insurrections in Tuscany could not be suppressed without measures of great severity, and Mendoza was consequently detested as a tyrant by all Italians who were not reconciled to the introduction of Spanish garrisons. In Sienna he was constantly exposed to assassination; and on one occasion, a musket ball directed against him killed the horse on which he rode. His intrepidity, however, was not to be shaken, and he continued to administer his difficult government until Paul III. died, and was succeeded by Julius III. a pope inclined to the Spanish party. The new pope wishing to bestow on Mendoza a particular mark of respect, appointed him Gonfalonier, or Standard-bearer to the church. In this character, Mendoza marched against the rebels in the ecclesiastical territories, and made them submit to the pope.