The Battle of Liège (5–16 August 1914) [also French: Bataille de Liège] was the opening engagement of the German invasion of Belgium and the first battle of the First World War. The city of Liège was protected by a ring of modern fortresses to form the Fortified position of Liège, one of several fortified cities to delay an invasion to allow troops from the powers which had guaranteed Belgian neutrality to assist the Belgian Army to expel the invaders.