The Chancellor of Prussia is Otto von Bismarck, a cold and patient calculator, convinced that German unity is built "with blood and iron." After defeating Austria in the war of 1866 and effectively unifying northern Germany, he needed one final step: to unite the southern German states under Prussian leadership. To do this, a common enemy was needed, and France was found to be it.
The tension stemmed from a dynastic issue. The vacant Spanish throne was offered to a German prince of the House of Hohenzollern. This was unacceptable to Paris, as it would mean being surrounded by dynasties linked to Prussia. Emperor Napoleon III reacted forcefully, and the candidacy was withdrawn. But the crisis was not resolved. France wanted more. It demanded a definitive guarantee: that no Hohenzollern would ever be a candidate for the Spanish throne. The French ambassador was sent to meet King Wilhelm I of Prussia in the spa town of Ems. The meeting was civil. The king listens, responds politely, but refuses to commit himself to the future. He considers the request excessive. After the meeting, he sends a report to Berlin. A neutral text. This is where Bismarck intervenes, taking the dispatch and editing it. He doesn't invent facts, but cuts and eliminates nuances. He transforms a diplomatic conversation into a brusque, almost offensive exchange. In the published text, it seems the king has dismissed the ambassador, and the ambassador has insisted provocatively. Both appear humiliated. In Paris, public opinion is inflamed, and national honour seems trampled. The government cannot back down. The same happens in Berlin.

Exactly as Bismarck intended, on July 19, 1870, France declared war on Prussia. The war is swift and devastating for France. Within weeks, the French army collapses, and Napoleon III is captured at Sedan. The French Empire collapses, while at Versailles, in 1871, the German Empire is born. Unification accomplished.

The Ems dispatch is brief, but it demonstrates something new. That war is not only prepared on the battlefield, but also built with words. Bismarck rewrote a message, and with those changes, he ignited a conflict that changed Europe.