After the defeat of Napoleon in the Battle of Leipzig in 1813, he was inaugurated as 'Sovereign Prince' of the United Netherlands. On March 16, 1815, he proclaimed himself king of the United Kingdom of the Netherlands and Duke of Luxembourg, after which he was inaugurated as King on 21 September 1815 in Brussels. In the same year, at the Congress of Vienna, the European powers decided to promote the Duchy of Luxembourg to the Grand Duchy and to recognize William as the first Grand Duke, with confirmation of the King's title. This formally recognized the brand-new Dutch monarchy within Europe. The new kingdom served as a buffer for both France and the United Kingdom. After the abdication in 1840 Willem I called himself King William Frederick, Count of Nassau. In Germany, from 1803 to 1806, William I was "Fürst" (prince) of the principality of Nassau-Oranje-Fulda. In 1806 and in the period 1813-1815 he was also Prince of the Principality of Nassau-Orange.Hardback, in German, 320 pages., 135 colour photos and 38 b/w images.