Occasion
The candidature of Prince Leopold of Hohenzollern Sigmaringen for the throne of Spain in 1870 was resented by France as calculated to bring Spain under the influence of Prussia. King William of Prussia, on representations from France, persuaded Prince Leopold to withdraw, but refused firmly but politely a guarantee against the renewal of the candidature. Bismarck published a telegram conveying the impression that the French Ambassador, Benedetti, had been insulted by the King at Ems on the occasion of the refusal. This infuriated public opinion in France, the Empress Eugénie actively used her influence, and Napoleon agreed to a declaration of war on July 14, 1870.