However, the purely defensive plans on which Napoleon III at first worked, were replaced in 1868 by offensive ones, in which General Lebrun took a prominent part, both from the military and from the diplomatic standpoints. It was not, however, until March, 1870, that the Archduke Albert of Austria came to Paris to confer with the French Emperor. Lebrun's plan of campaign was discussed by them, and Marshal Le Boeuf and Generals Frossard and Jarras were privy to the negotiations. It was proposed that France, Austria, and Italy should invade Germany conjointly; and, according to Le Boeuf, the first-named Power could place 400,000 men on the frontier in a fortnight's time. Both Austria and Italy, however, required forty-two days to mobilize their forces, though the former offered to provide two army corps during the interval. When Lebrun subsequently went to Vienna to come to a positive decision and arrange details, the Archduke Albert pointed out that the war ought to begin in the spring season, for, said he, the North Germans would be able to support the cold and dampness of a winter campaign far better than the allies. That was an absolutely correct forecast, fully confirmed by all that took place in France during the winter of 1870-1871. But Prussia heard of what was brewing. Austria was betrayed to her by Hungary; and Italy and France could not come to an understanding on the question of Rome. At the outset Prince Napoleon (Jerome) was concerned in the latter negotiations, which were eventually conducted by Count Vimercati, the Italian military _attache_ in Paris. Napoleon, however, steadily refused to withdraw his forces from the States of the Church and to allow Victor Emmanuel to occupy Rome. Had he yielded on those points Italy would certainly have joined him, and Austria--however much Hungarian statesmen might have disliked it--would, in all probability, have followed suit. By the policy he pursued in this matter, the French Emperor lost everything, and prevented nothing. On the one hand, France was defeated and the Empire of the Bonapartes collapsed; whilst, on the other, Rome became Italy's true capital. Bismarck was in no way inclined to allow the negotiations for an anti-Prussian alliance to mature. They dragged on for a considerable time, but the Government of Napoleon III was not particularly disturbed thereat, as it felt certain that victory would attend the French arms at the outset, and that Italy and Austria would eventually give support. Bismarck, however, precipitated events. Already in the previous year Prince Leopold of Hohenzollern-Sigmaringen had been a candidate for the throne of Spain. That candidature had been withdrawn in order to avert a conflict between France and Germany; but now it was revived at Bismarck's instigation in order to bring about one.