In January 1712, the count of Waldeck and Pyrmont was elevated to prince by Charles VI, Holy Roman Emperor. For a brief period, 1805 to 1812, Pyrmont was a separate principality as a result of inheritance and partition after the death of the previous prince, but the two parts were united again in 1812. The independence of the principality was confirmed in 1815 by the Congress of Vienna, and Waldeck and Pyrmont became a member of the German Confederation. From 1868 onward, the principality was administered by Prussia, but retained its legislative sovereignty. Prussian administration served to reduce administrative costs for the small state and was based on a ten-year contract that was repeatedly renewed for the duration of its existence. In 1871, the principality became a constituent state of the new German Empire. At the end of World War I, during the German Revolution that resulted in the fall of all the German monarchies, the prince abdicated and the principality became the Free State of Waldeck-Pyrmont within the Weimar Republic.