In the early stages of World War 1 some 800,000 German troops defied Belgian neutrality and marched across the border. In August 1914 the bulk of the German army - some 800,000 troops - defied Belgian neutrality and smashed across the border. Their orders were to invade France, destroying any Belgian resistance in their path. The German commanders were to achieve this within 6 weeks. What followed was the rape and massacre of hundreds of Belgian civilians. Scores of villages were burned. The beautiful library at Louvain was left in ashes. Such crimes were not arbitrary acts of drunken violence. They were planned and approved under the German military code. In this extract from his book 1914: The Year the World Ended , historian Paul Ham shows how the invasion of of Belgium set a brutal precedent for the Nazi occupation of Europe, 25 years later