The city on the Vltava, also known as the city of 100 towers or the Golden City, is considered one of the most beautiful capitals of Europe. Since 1992 the entire historical old town has been declared a World Heritage Site. The region has been densely populated since prehistoric times. In the 6th century the Slavs settled there first. German and Jewish merchants made the city one of the main trading centers of Central Europe in the 10th century. The real heyday of Prague began in the 14th century with Charles IV. who became King of Bohemia in 1346. The Charles Bridge and Charles University, which is the oldest university north of the Alps, bear his name. Until World War II the city was inhabited by Czechs, Germans and Jews. Especially for the German culture the city has contributed substantially, as evidenced in names such as Albert Einstein, Franz Kaffka or Rainer Maria Rilke.