The contribution of Otto van Bismarck the architect of this process carried out with the help of the Prussian army and bureaucracy. Three wars over seven years – with Austria, Denmark and France – ended in Prussian victory and completed the process of unification. In January 1871, the Prussian king, William I, was proclaimed German Emperor in a ceremony held at Versailles. Otto von Bismarck gathered in the unheated Hall of Mirrors in the Palace of Versailles to proclaim the new German Empire headed by Kaiser William I of Prussia.