What happened on 10 May 1940?
On 10 May 1940 Germany attacked the neutral Netherlands, Belgium and Luxembourg and opened its offensive against France. Glider troops landed on the Belgian fort of Eben-Emael and seized bridges over the Albert Canal, paratroopers came down around The Hague and Rotterdam, and German armor drove into Luxembourg and the Ardennes. The British and French armies advanced into Belgium to meet the attack, which was what the German plan expected. Three days later German troops crossed the Meuse near Sedan, and on 20 May they reached the Channel.9
The morning of 10 May 1940 ended eight months of the "phoney war" in the West. Within six weeks the Netherlands and Belgium had capitulated, the British army had been carried home from Dunkirk and France had signed an armistice. This article follows the first days of the German offensive, the airborne attacks, the Allied march into Belgium and the thrust through the Ardennes, and then sketches how they led to Sedan and Dunkirk. The wider war in the West is told in our guide to the Western Front in World War II.10
Two plans for one front
Britain and France had been at war with Germany since September 1939, after the German invasion of Poland, but along the French border almost nothing happened through the winter. The Netherlands, Belgium and Luxembourg stayed neutral and hoped to be spared the war.11
The Allies expected the main German blow to come through central Belgium. Their answer, known as Plan D or the Dyle plan, was to march into Belgium as soon as it was attacked and hold a line along the river Dyle, east of Brussels, with the Belgian army on their left. The French Seventh Army was to push farther north, toward Breda in the Netherlands, to cover the mouth of the Scheldt. The British official history notes that once the French had ruled out an attack through the wooded Ardennes, no further thought seems to have been given to it.12
The German plan had changed. The attack was first meant for the autumn and winter of 1939 and was postponed many times, and after the postponement in January it was recast. Army Group B was now to attack the Netherlands and Belgium and draw the Allies forward, while the main effort, Army Group A under Gerd von Rundstedt, would cross Luxembourg and the Ardennes toward the Meuse. The German Historical Museum credits this "sickle cut" plan to Erich von Manstein. The British official history counts 44 divisions, 7 of them armored, in Army Group A and only 28, 3 armored, in Army Group B.13
Dawn on 10 May
10 May. Before dawn German aircraft bombed airfields, railway stations and communication centers in the Netherlands, Belgium and France. By the Belgian official account, the Belgian air force was caught on the ground and lost more than half of its machines. The British official history gives the German zero hour for the ground attack as 5.35 in the morning.14
The attack came without a declaration of war. In Brussels Foreign Minister Paul-Henri Spaak appealed to Britain and France for help, and the same morning the Allied supreme command ordered Plan D into action. By the evening the first British troops were on the Dyle between Wavre and Louvain, with French cavalry on their right toward Namur.15
Luxembourg had only a small, lightly armed force and no fortifications, and could not stop the invasion. After a few skirmishes its men laid down their arms. Grand Duchess Charlotte and her government left the country and later settled in London.16
Eben-Emael and the Albert Canal
The Belgian plan was to fight a delaying action on the Albert Canal and the Meuse until the Allies reached the Dyle. Its strongest point was the fort of Eben-Emael, south of Maastricht, whose guns covered the canal bridges at Vroenhoven, Veldwezelt and Briedgen.17
In the dark, a few German gliders landed on the roof of the fort. Their crews blew up or damaged its guns with explosives, while other glider troops, reinforced by paratroopers, landed behind the three bridges and took them from the rear. The Smithsonian's National Air and Space Museum puts the force on the fort at 85 men in 11 DFS 230 gliders, and writes that it neutralized the fort in about 20 minutes.18
The Belgians counterattacked and won back and destroyed the bridge at Briedgen, but the Germans held Vroenhoven and Veldwezelt. The Belgian official account records that a squadron sent to bomb the bridge at Vroenhoven lost eleven of its twelve aircraft. The fort itself fell on 11 May, by the Belgian official account, and German armor poured through the gap toward Tongeren. That evening the Belgian command ordered the withdrawal from the Albert Canal to the line from Antwerp to Namur.19
Allied air help came late and at a heavy price. The Belgian official account says its requests for bombers went unanswered until midday on 11 May. British and French bombers attacked the Maastricht bridges that day with little success, and on 12 May the RAF tried again. The British official history records that five Fairey Battles of No. 12 Squadron, flown by volunteers, made the second attack and only one came back. Its leading pilot and navigator, Flying Officer D. E. Garland and Sergeant T. Gray, received the first Victoria Crosses of the campaign, both posthumously.20
The same day King Leopold, General Pownall representing Lord Gort, and the French generals Georges and Billotte met at the Château de Casteau near Mons. They agreed that General Billotte, commander of the French army group in the north, would coordinate the Allied armies in Belgium. The British official history judges that the arrangement worked only haltingly.21
The airborne attack on Fortress Holland
The Dutch planned their last stand in Fortress Holland, the heart of the country around Amsterdam, Utrecht and Rotterdam, protected by floods. The Germans meant to break it from the inside on the first day: to seize the seat of government at The Hague and, by the German Historical Museum's account, to capture Queen Wilhelmina.22
Paratroopers dropped on the airfields of Valkenburg, Ypenburg and Ockenburg around The Hague and took them, and transport aircraft began to land airborne infantry. The Dutch counterattacked the same day and by the evening had retaken all three airfields, and the attempt on The Hague failed.23
In the south the attack went better for the Germans. Paratroopers seized the bridges over the Maas in Rotterdam and the airfield of Waalhaven, and took the long road and rail bridges at Moerdijk intact. The Dutch could not retake the Rotterdam bridges, and the Germans could not take the city north of the river.24
Those bridges decided the campaign. The French Seventh Army, sent toward Breda, did not retake the Moerdijk bridges and fell back into Belgium. On 12 May German armor that had crossed North Brabant reached the Moerdijk bridges and drove north into Fortress Holland, cutting the Dutch army off from the Allies. By 13 May it had joined the paratroopers on the south bank of the Maas at Rotterdam.25
Rotterdam and the Dutch capitulation
14 May. The Dutch still held the east front of Fortress Holland and the north bank of the river in Rotterdam. That morning the Germans threatened to destroy Rotterdam and Utrecht from the air unless resistance ended. While the Dutch were negotiating, German bombers struck the center of Rotterdam. The German Historical Museum counts 57 bombers, the Dutch official account of 1944 at least fifty, and the museum adds that a recall order reached only part of the formation.26
The old city was burned out. The German Historical Museum gives over 800 civilian dead and 78,000 homeless, and the Anne Frank House about 850 dead and close to 80,000 homeless.27
With Utrecht and other cities threatened and no Allied help in sight, General Henri Winkelman, the Dutch commander-in-chief, decided to capitulate. The Dutch troops laid down their arms on the afternoon of 14 May, and Winkelman signed the capitulation on 15 May. The Dutch official account notes that the troops in Zeeland were left out of it and fought on for a few more days. Queen Wilhelmina and the government had already left for London.28
The long Dutch story of floods, fortresses and wars is told in the military history of the Netherlands.
Through the Ardennes to Sedan
The French staff had judged the Ardennes "impracticable for tanks," as the British official history quotes it, and the German Historical Museum and English Heritage both note that the wooded hills were thought impassable for a large armored force. While the Allies watched the north, the tank columns of Army Group A were working their way along the narrow roads of Luxembourg and the Belgian Ardennes. French cavalry and light tanks sent forward into the Ardennes met them and were pulled back.29
By the night of 12 May all the outposts of the French Ninth Army had gone back behind the Meuse. That night and on 13 May German troops crossed the river at several points and formed bridgeheads on the west bank near Sedan and Dinant. At Sedan the crossing was made by the panzer corps of Heinz Guderian. According to the German Historical Museum, the French had only 18 divisions along the Ardennes and the middle front.30
The breakthrough on the Meuse turned the Dyle plan into a trap. The best French and British divisions were in Belgium, facing east, while the German armor behind their right flank faced open country all the way to the sea.31
To the sea, Dunkirk and the armistice
20 May. German armor reached the Channel coast at Abbeville, at the mouth of the Somme. The war diary of Army Group A, quoted in the British official history, noted that the first stage of the offensive had been achieved. The Allied armies in Belgium and northern France were cut off from the rest of France.32
The Belgian army fell back with the Allies to the Scheldt. On the evening of 27 May King Leopold III, who commanded it in person, asked the Germans for terms and was told the surrender must be unconditional. The Belgian army laid down its arms on 28 May, at four in the morning by the Belgian official account.33
The British Expeditionary Force, with a large French contingent, fell back on Dunkirk. Between 26 May and 4 June Operation Dynamo brought 338,226 British and Allied soldiers to England. The full story is in our article on the Dunkirk evacuation.34
On 5 June the Germans attacked across the Somme and the Aisne (Fall Rot), on 14 June they entered Paris, and on 22 June France signed an armistice. Six weeks after 10 May, the campaign in the West was over.35
For the Netherlands, Belgium and Luxembourg, 10 May 1940 began years of German occupation. Luxembourg was placed under a German civil administration in the summer of 1940 and annexed in 1942, and it was liberated in September 1944.36
