"Kurpfälzisch" is spoken on the right bank of the Rhine. The difference to the Pfalz dialect spoken on the left bank is minimal. The Palatinate language area extends from Mannheim and Viernheim in the North to Weinheim, Heidelberg and Wiesloch towards Bruchsal in the South. In the East, it reaches the Baden Odenwald from Neckargemünd to Eberbach, Mosbach and Sinsheim. Approximately 1,500,000 people live in the area where Kurpfälzisch language is spoken. The historical Electoral Palatinate has its roots in the Rhenish-Lorraine Palatinate, the core areas of which country were initially located further to the North. The territory was moved later to the South, where it remained until its division, as a result of the house of the Ezzonids dying out in the 11th century. After County of Palatine had been allotted to various ruling houses, the rule of the Wittelsbacher began in the 13th century. Through this family, the County Palatine, which was soon to be called "Kurpfalz", gained great political importance in Southern Germany. After the Bavarian Wittelsbacher lineage died out, the Electorate of Bavaria went to the Palatine lineage in 1777. As a result, the Electorate of Palatinate-Bavaria was formed until the division of the Electoral Palatinate. The part of the Palatinate which is located on the left side of the Rhine became French during the French revolutionary wars but later became part of the kingdom of Bavaria after the subversion of Napoleon Bonaparte. The core territory of the Electoral Palatinate between the Rhine and the Neckar became part of the Grand Dutchy of Baden because of the Reichsdeputationshauptschluss in 1803 and shared its history from that point onwards (see Baden in the 19th century). Mannheim's mayor, Hermann Heimerich, attempted to overcome the division of the old Electoral Palatinate in 1948, which ultimately failed. One reason for this was that, because of their unity, the South German territorial states had an advantage over the divided character of the Electoral Palatinate. Cities like Worms, Speyer or Bruchsal could not identify themselves with the historical Electoral Palatinate. In 2005, the metropolitan area Rhine-Neckar was formed through a treaty which aimed to strengthen and facilitate trans-national cooperation.