The Franco-Prussian War was fought between France and Prussia with a coalition of German states from 15 July 1870 to 1 February 1871. Prussian leadership of the German states had been confirmed after the defeat of Austria by Prussia in the Seven Weeks' War in 1866. This threatened France's position as the dominant power in Europe. The candidacy of Prince Leopold for the Spanish throne was one of the immediate causes of the Franco-Prussian war. It was Otto von Bismarck, the Prussian chancellor and de facto leader of Spain, Juan Prim, who persuaded Leopold, very reluctantly, to accept the Spanish throne in June 1870. This move was alarming for France, the possible combination of Prussia and Spain directed against it he was threatening. Leopold's candidacy was withdrawn under French diplomatic pressure. The French ambassador asked them to promise that Leopold would never again be allowed to run for the Spanish throne, which King William I politely refused. A telegram describing this incident was sent to Bismarck. In which he modified the original description and on July 14 he ...