Despite the recent assertions of the French minister, M. Ollivier, it is probable that the Empire of Louis Napoleon had lost all its allies. Austria, anxious to avenge Sadowa, was restrained by the threat of the intervention of Russia; that power still considered the dual empire its rival in the Balkans and still remembered the Crimea; an offensive and defensive alliance had been concluded by Prussia with the German states south of the Main. Thus prepared, the chancellor waited for an opportunity, and as none presented itself soon enough, he made one. The revolution in Spain in 1868 had driven Queen Isabella into exile and left her throne vacant; Marshal Prim, who retained the reins of power, was negotiating in the different courts of Europe to find an acceptable new sovereign. At the beginning of July, 1870, Paris was surprised to hear that the candidate chosen by him, and who would probably be proclaimed by the Cortès, was Prince Leopold of Hohenzollern. This negotiation had been carried on secretly, the French ambassador at Madrid had been informed of nothing, and from Marshal Prim's documents it was afterward learned that Bismarck himself had suggested the prince for the crown. It was very certain that France would oppose this union of the dynasties of Berlin and Madrid, and, in fact, on the 6th of July the government sent a message to the Chamber protesting against this candidature and declaring that it would be compelled to oppose it, if necessary, to the last extremity. Three days later, M. Benedetti, the French ambassador at Berlin, sought an interview with the King of Prussia at Ems, where he was taking the waters, and requested him, as head of the Hohenzollern family, not to give his consent to the candidature of Prince Leopold. The king replied that, in this affair, he had intervened not as King of Prussia but as head of the family, and the interview ended without any definite assurances on his part. However, Prince Anthony of Hohenzollern, the father of Leopold, officially announced that his son was no longer a candidate. Then the French diplomacy came to Bismarck's aid by committing a great blunder; M. Benedetti sought another interview with the king, who had not yet heard of this withdrawal, informed him of it, and requested him to give the French government formal assurance that Prince Leopold would abide by it. This promise the king refused to give, but he notified the ambassador that he would inform him when he had received a confirmation of the renunciation. When this was received, he sent word to M. Benedetti by an aide-de-camp, refusing him the third audience which he requested, stating that he approved of the prince's decision, but declining to bind himself with regard to any future negotiations.