The fortified position of Liège was established following World War I by Belgium to fortify the traditional invasion corridor from Germany through Belgium to France. The Belgian experience of World War I, in which the Belgian Army held the invading force for a week at Liège, impeding the German timetable for the conquest of France, caused Belgium to consider a refined defence strategy. Belgium upgraded the existing fortifications of Liège and extended them onto the Herve plateau closer to Germany, using the most advanced fortifications available to Belgian military technology. However, in 1936, Belgium's neutrality was proclaimed by King Leopold III of Belgium in a vain attempt to forestall another conflict, preventing France from being able to make active use of the Belgian defences and t