Worms is a city in Rhineland-Palatinate (Rheinland-Pfalz), in western Germany, situated on the River Rhine. It has a population of 82,000, and is one of the oldest cities in Germany. Parts of the legendary Song of the Nibelungs (German: Nibelungenlied) took place at Worms, but outside from mythology, Worms is best known as the location of the Diet of Worms in 1521 (Diet meaning parliament or assembly), a parliament of the Holy Roman Empire at which Martin Luther was declared an outlaw. The mayor of Worms is Michael Kissel, a member of left-center SPD.