 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 territory in the forward defence of France.At the outbreak of World War II, Belgium's defences had to resist alone until France could advance into Belgium after neutrality failed.