By this ceremony, the North German Confederation was transformed into the German Empire. This empire was a federal monarchy; the emperor was head of state and president of the federated monarchs (the kings of Bavaria, Württemberg, Saxony, the grand dukes of Oldenburg, Baden, Mecklenburg-Schwerin, Hesse, as well as other principalities, duchies and of the free cities of Hamburg, Lübeck and Bremen).