On this day in 1940, the Battle of Belgium, which had been fought for just 18 days between Allied forces and Germany, ended with the German occupation of Belgium after the surrender of the Belgian Army. Before the Second World War broke out, King Leopold III of Belgium had advocated an independent foreign policy for Belgium, twice urging mediation of the conflict between Nazi Germany and the Western Allies in the months immediately before and after the outbreak of war in 1939.
Depite the original German invasion in 1914, Belgium returned to a policy of neutrality after the First World War, which was heavily supported by the Belgian population. However, on 10 May 1940, Germany invaded for a second time, striking at both the Netherlands and Belgium. It was the start of the long-anticipated German offensive in the West.
After 18 days of fighting, King Leopold surrendered the Belgian Army without the consultation of the Cabinet or the Allied forces, which resulted in the withdrawal of the Allies from continental Europe. Leopold was held prisoner by the Germans until the end of the war.