Germany has an urban history of more than 2,000 years. The Romans founded a dense network of colonial cities in the then province 'Germania', with cities such as Augsburg, Regensburg, Trier, Xanten or Cologne. The Middle Ages saw the emergence of independent cities and the powerful networks of Hanseatic cities. Germany benefits from its decentralized federal system. This system was established by the allied forces in West Germany after the second world war, built on a long history of scattered regionalism in Germany, labelled Kleinstaaterei, in the 18th and early 19th century. While, prior to 1989, the urban systems in East and West Germany developed quite differently for more than 40 years, the reunification allowed their full integration into the established West German system, to immediate effect. The main income of local authorities in Germany is a 15 per cent share of revenues from wage and income tax.