Still, Belgians knew the real danger lay to the east, and they had begun mobilizing their armed forces on 25 August 1939. By May 1940, their country fielded an army of more than 600,000 men organized into 22 divisions: 18 infantry divisions, 2 partially motorized Chasseurs Ardannais divisions, and 2 motorized cavalry divisions. Unfortunately for Belgium, this sizable force was hardly equipped to defeat a German invasion. The Belgians possessed few antiaircraft guns and had only 42 light and 12 medium tanks. Their air service had only 184 operational aircraft. Thus, Belgium had no hope of winning a prolonged land campaign with Germany without outside assistance.
German Colonel General Fedor von Bock's Army Group B operated against Belgium and the Netherlands. The Germans committed Colonel General Walther von Reichenau's Sixth Army, with 17 infantry and 2 tank divisions, to the initial invasion of Belgium. It was to drive southwest. Meanwhile, General of Artillery (Lieutenant General) Georg von Küchler's Eighteenth Army of 11 divisions (9 infantry and 1 each of cavalry and tanks) was expected to subdue the Netherlands quickly and then drive south to join the fighting in Belgium.
Although Belgian intelligence accurately forecast the German attack that occurred on 10 May 1940, no one anticipated the audacious German attack on the fortress of Eben Emael in the first hours of the fighting. Eben Emael was a series of concrete and steel emplacements north of Liège that guarded bridges over the Albert Canal at Briedgen, Veldwezelt, and Vroenhoven. Garrisoned by more than 700 men, the fortress was crucial to Belgian defensive plans because the only hope of slowing the German panzers lay in keeping them east of the canal. German army planners took special notice of Eben Emael for that very reason, and at 5:25 a.m. on 10 May 1940, they sent 78 specially trained men of the Kock Assault Detachment in gliders to crash-land on top of the fortress. The attackers employed hollow charges to destroy the key gun turrets and bunkers. At the same time, German paratroopers captured the major bridges. Troops of the 223rd Infantry Division followed close behind and took the rest of the Belgian position the next day. In less than 24 hours, the Germans had breached the key Belgian defensive line on the Albert Canal.
Fighting bravely, the Belgians fell back to the Dyle Line east of Brussels, with King Leopold III in personal command. The British and French had planned to send their own forces into Belgium in the event of a German invasion, but there had been little prior coordination between Britain, France, and neutral Belgium. On 12 May, however, elements of the British Expeditionary Force (BEF) and General Georges Blanchard's French First Army began joining the Belgian defenders, and by 15 May, the Allies had some 35 divisions in the Namur-Antwerp area.
As Reichenau's Sixth Army probed the Dyle Line, Georg von Küchler's Eighteenth Army turned south from the Netherlands after the surrender of that country to the Germans on 15 May. This move threatened the Allied left flank. At the same time and to the south, the hammer blow of Colonel General (Karl) Gerd von Rundstedt's Army Group A, heavy in tanks, was driving west and then north through the Ardennes Forest. The overall German plan, Operation sichelschnitt (the cut of the sickle), worked to perfection.
On 25 May, King Leopold III met with his ministers at the chateau of Wynendaele to discuss the possibility of surrender. His ministers wanted to flee to Great Britain and continue the war on the Allied side, but Leopold, despite a pledge to the British and French not to surrender unilaterally, believed that the campaign was lost and that he should end the fighting to save bloodshed and then remain to share the fate of his people. Leopold indeed took this step, surrendering the Belgian armed forces on 28 May. This step exposed the left flank of the British-French line and ended any Allied hopes of holding part of Flanders. British Prime Minister Winston L. S. Churchill then ordered the British navy to evacuate British forces at Dunkerque.
The 18 days of the Belgian Campaign cost the nation some 7,500 troops killed in action and 15,850 wounded. And at least 2,000 Belgian prisoners of war died in German captivity. The country remained under German occupation for the next four years. Lance Janda and Spencer C. Tucker
Deighton, Len. Blitzkrieg: From the Rise of Hitler to the Fall of Dunkirk. New York: Alfred A. Knopf, 1980.; Messenger, Charles, and John Keegan, eds. The Second World War in the West (The History of Warfare). London: Cassell Academic, 1999.; Mrazek, James E. The Fall of Eben Emael. Reprint ed. Presidio, 1999.; Powaski, Ronald E. Lightning War: Blitzkrieg in the West, 1940. Indianapolis, IN: John Wiley and Sons, 2002.
Lance Janda and Spencer C. Tucker