On the 18th January 1871, Wilhelm I of Prussia was proclaimed the first German Emperor. The creation of the federal Empire made Wilhelm the head of state and president of the federated monarchies that made up the 27 constituent territories.
Wilhelm had been made the President of the North German Confederation on its formation in 1867, and during the Franco-Prussian War took a leading role in the command of the German forces. With patriotic fervour as a result of the enormously successful German advance, in November 1870 the remaining states south of the river Main joined the North German Confederation.
The next month, on the 10th December, the Reichstag of the Confederation renamed itself the German Empire. Wilhelm was formally declared the German Emperor in the Hall of Mirrors at the Palace of Versailles on the 18th January. The title was accepted grudgingly by Wilhelm who would have preferred “Emperor of Germany” rather than “German Emperor”, but Bismarck warned that this would be dangerous as it suggested he had a claim to other Germanic lands such as Austria, Luxembourg and Switzerland. He also refused to be titled “Emperor of the Germans”, since this would have suggested he ruled with permission from the German people rather than by “the grace of God”. As a believer in divine right, this suggestion was unacceptable to him.
Three months later, on the 14th April, the Reichstag adopted the German Constitution. This stated that the King of Prussia would be the permanent President of the confederation of states that formed the Empire. Therefore, the role of Emperor was directly tied to the Prussian crown.