After the Battle of Leipzig in 1813, the French were driven out of Hesse-Kassel, and on 21 November, the Elector returned in triumph to his capital, Kassel. A treaty concluded by him with the Coalition (2 December) stipulated that he was to receive back all his former territories, or their equivalent, and at the same time restored the ancient constitution of his country. This treaty, so far as the territories were concerned, was implemented by the Great Powers at the Congress of Vienna. They refused, however, the Elector's request to be recognized as "King of the Chatti" ("König der Katten"). At the Congress of Aix-la-Chapelle (1818), he was listed with the grand dukes as a "Royal Highness." William chose to retain the now empty title of prince-elector, with the predicate of "Royal Highness".