In the following year the Zollverein, or German Customs' Union (which had been gradually growing since 1833), took a definitely national form in a Customs' Parliament which assembled in April 1868, thus unifying Germany for purposes of trade as well as those of war. This sharp rebuff came at a time when Napoleon's throne was tottering from the utter collapse of his Mexican expedition; when, too, he more than ever needed popular support in France for the beginnings of a more constitutional rule. Early in 1867 he sought to buy Luxemburg from Holland. This action aroused a storm of wrath in Prussia, which had the right to garrison Luxemburg; but the question was patched up by a Conference of the Powers at London, the Duchy being declared neutral territory under the guarantee of Europe; the fortifications of its capital were also to be demolished, and the Prussian garrison withdrawn. This success for French diplomacy was repeated in Italy, where the French troops supporting the Pope crushed the efforts of Garibaldi and his irregulars to capture Rome, at the sanguinary fight of Mentana (November 3, 1867). The official despatch, stating that the new French rifle, the _chassepôt_, "had done wonders," spread jubilation through France and a sharp anti-Gallic sentiment throughout Italy. And while Italy heaved with longings for her natural capital, popular feelings in France and North Germany made steadily for war. Before entering upon the final stages of the dispute, it may be well to take a bird's-eye view of the condition of the chief Powers in so far as it explains their attitude towards the great struggle. The condition of French politics was strangely complex. The Emperor had always professed that he was the elect of France, and would ultimately crown his political edifice with the corner-stone of constitutional liberty. Had he done so in the successful years 1855-61, possibly his dynasty might have taken root. He deferred action, however, until the darker years that came after 1866. In 1868 greater freedom was allowed to the Press and in the case of public meetings. The General Election of the spring of 1869 showed large gains to the Opposition, and decided the Emperor to grant to the Corps Législatif the right of initiating laws concurrently with himself, and he declared that Ministers should be responsible to it (September 1869).