Ems dispatch in the context of Wilhelm I

The Franco-Prussian War or Franco-German War, often referred to in France as the War of 1870, was a conflict between the Second French Empire and the North German Confederation led by the Kingdom of Prussia. Lasting from 19 July 1870 to 28 January 1871, the conflict was caused primarily by France's determination to reassert its dominant position in continental Europe, which appeared in question following the decisive Prussian victory over Austria in 1866.

After a prince of the Roman Catholic branch Hohenzollern-Sigmaringen had been offered the vacant Spanish throne in 1870 and had withdrawn his acceptance, the French ambassador approached Prussian King Wilhelm I at his vacationing site in Ems demanding Prussia renounce any future claims, which Wilhelm rejected. The internal Ems dispatch reported this to Berlin on July 13; Prussian chancellor Otto von Bismarck quickly then made it public with altered wording. Thus the French newspapers for July 14, the French national holiday contained translations of Bismarck's press release, but not a report from their own ambassador. A crowd in the streets of Paris demanded war, and soon French mobilization was ordered.