Siena was quieted, but not satisfied, while a new treaty between Charles V. and France took from them their hope of recurring to the assistance of the latter. After the peace, don Juan de Luna commanded at Siena, with a small Spanish garrison. But still the seeds of discontent and of revolt, fostered by an ardent attachment to their ancient institutions, lay germinating in the hearts of the citizens. Charles never sent pay to his soldiers: during time of war they lived by booty, in time of peace, by extortion; love of liberty, and hatred of their oppressors, joined to cause them to endeavour to throw off the foreign yoke. On the 6th of February 1545, the people rose in tumult; about thirty nobles were killed, the rest took refuge in the palace with don Juan de Luna. The troops of Cosmo I. hovered on the frontier. He, perhaps, fostered the revolt for his own ends; at least, he was eager to take advantage of it, and wished the Spanish governor to call in his aid to quell it. But don Juan wanted either resolution or foresight; he allowed the Spanish garrison to be dismissed, and, finally, a month afterwards, was forced to quit the town, accompanied by the obnoxious members of the aristocracy. For sometime Siena enjoyed the popular liberty which they had attained, till circumstances led the emperor to fear that the French would gain power there; and he resolved to reduce the city to unqualified submission. Mendoza was then ambassador at Rome. Charles named him captain-general of Siena, and gave him orders to introduce a Spanish garrison, and even to build a citadel for its protection. Mendoza obeyed: as the subject of a despotic sovereign, he felt no remorse in crushing the liberties of a republic. He did not endeavour to conciliate, nor to enforce respect by the justice of his measures. He held the discontented and outraged citizens in check by force of arms only; disarming them, and delivering them up to the insolence and extortion of the Spanish soldiery. They could obtain no protection against all the thousand injuries, thefts, and murders to which they were subjected. Mendoza, haughty and unfeeling, became the object of universal hatred. Complaints against him were carried to the emperor, and, when these remained without effect, his life was attempted by assassination: on one occasion his horse was killed under him by a musket shot, aimed at himself. But Mendoza was as personally fearless as he was proud; and the sternness that humanity could not mitigate, was not softened by the suggestions of caution.