In an attempt to capture Paris by passing through neutral countries, the German army demanded free passage through Belgium. Determined to maintain its neutral status in the war, the Belgian government refused, whereupon German troops invaded Belgium on 4 August 1914. The Belgians in turn picked up their weapons and joined the Allies. It quickly transpired that the small Belgian army was no match for the powerful German offensive. The fortified position of Liège, as well as major cities such as Leuven, Brussels, Mechelen and Antwerp, were overthrown one after another. As the German army advanced, the Belgian, French and British troops retreated towards the Westhoek.