Germany's war against the Western Allies

On September 1, 1939, Germany invaded Poland, using the false pretext of a faked "Polish attack" on a German border post. On September 3, the United Kingdom issued an ultimatum to Germany. No reply was received, and Britain, Australia and New Zealand declared war on Germany, followed later that day by France. Soon afterwards, South Africa, Canada and Nepal also declared war on Germany. Immediately, the UK began seizing German ships and implementing a blockade.

Despite the French and British treaty obligations and promises to the Polish government, both France and the UK were unwilling to launch a full invasion of Germany. The French mobilized slowly and then mounted only a short token offensive in the Saar; neither did the British send land forces in time to support the Poles. Meanwhile, on September 8, the Germans reached Warsaw, having ripped through the Polish defenses. On September 17, the Soviet Union, pursuant to its prior agreement with Germany, invaded Poland from the east. Poland was soon overwhelmed, and the last Polish units surrendered on October 6.


French and British soldiers taken prisoner at Dunkirk during the Battle of France.


French and British soldiers taken prisoner at Dunkirk during the Battle of France.



After Poland fell, Germany paused to regroup during the winter while the British and French stayed on the defensive. The period was referred to by journalists as "the Phoney War" because of the inaction on both sides. In Eastern Europe, the Soviets began occupying Baltic states leading to a confrontation with Finland, a conflict which ended with land concessions to the Soviets on March 12, 1940. In early April 1940, both German and Allied forces launched nearly simultaneous operations around Norway over access to Swedish iron ore. It was a two month campaign which resulted in complete German control of Denmark and Norway, though at a heavy cost to their surface navy. The fall of Norway led to the Norway Debate in London, which resulted in the resignation of Prime Minister Neville Chamberlain, who was replaced by Winston Churchill.

On May 10, 1940, the Germans invaded France and the Low Countries. The British Expeditionary Force (BEF) and the French Army advanced into Flanders and planned to fight a mobile war in the north, while maintaining a static continuous front along the Maginot Line further south. This was foiled by an unexpected German thrust through the Ardennes, splitting the Allies in two. The BEF and French forces, encircled in the north, were evacuated from Dunkirk in Operation Dynamo. Italy attacked France in the Alps in June 10, 1940. France, overwhelmed by the blitzkrieg, was forced to sign an armistice with Germany on June 22, 1940, leading to the direct German occupation of Paris and two-thirds of France, and the establishment of a German puppet state headquartered in southeastern France known as Vichy France.


Bombed buildings in London during the The Blitz.


Bombed buildings in London during the The Blitz.



With only the United Kingdom remaining as an opposing force in Europe, Germany began to prepare Operation Sealion, the invasion of Britain. Most of the British Army's heavy weapons and supplies had been lost at Dunkirk, but the Royal Navy was still stronger than the Kriegsmarine and kept control of the English Channel. The Germans then attempted to gain air superiority by destroying the Royal Air Force (RAF) using the Luftwaffe. The ensuing air war in the late summer of 1940 became known as the Battle of Britain. The Luftwaffe initially targeted RAF Fighter Command aerodromes and radar stations, but Luftwaffe Commander Hermann Göring and Hitler, angered by British bombing raids on German cities, switched their attention towards bombing English cities, an offensive which became known as The Blitz. This diversion of resources allowed the RAF to rebuild their airbases, eventually leading Hitler to give up on his goal of establishing air superiority over the English Channel; this in turn led to the permanent postponing of Operation Sealion.

With Germany and her allies having total control of the continent, the United Kingdom and its allies settled for strategic bombing and special forces operations in mainland Europe. Many of the conquered nations formed governments in exile and military units within the United Kingdom as well as domestic resistance movements. Germany, meanwhile, fortified its position by constructing the Atlantic Wall.