The Rhine Neckar region was part of the territory of the Prince-elector of the "Kurpfalz", or Electorate of the Palatinate, one of the larger states within the Holy Roman Empire. The foundation of the new capital of the Kurpfalz, Mannheim, was a decisive influence on the development of the area as a whole. Parallel to the foundation of Mannheim in 1606, a fortress ("die Rheinschanze") was built by Frederick IV, Elector Palatine on the other side of the Rhine to protect the City of Mannheim, thus forming the nucleus of the City of Ludwigshafen itself.