Key facts and dates

The period between 1939 and 1941 marked the rapid expansion of Axis powers across Europe, North Africa, and into Asia, setting the stage for a global conflict. This timeline captures the pivotal events of Axis military campaigns during the early years of the Second World War.

Timeline of key events

• 1 September 1939 – Germany invades Poland, initiating the Second World War.
• 17 September 1939 – Soviet Union invades Poland from the east, leading to its partition.
• 30 November 1939 – Soviet Union invades Finland, starting the Winter War.
• 9 April 1940 – Germany invades Denmark and Norway, securing strategic positions.
• 10 May 1940 – Germany invades France through the Ardennes, leading to its fall by June.
• July-October 1940 – Battle of Britain sees the RAF repel the Luftwaffe, halting invasion plans.
• 22 June 1941 – Operation Barbarossa begins with Germany's invasion of the Soviet Union.
• 7 December 1941 – Japan attacks Pearl Harbor, bringing the USA into the war.

The invasion of Poland and the early war (1939)

The Second World War began with Germany's aggressive expansion into Poland, marking the start of a conflict that would engulf much of the world. This initial phase saw rapid territorial gains for the Axis powers and set the tone for their military strategies.

Blitzkrieg and the conquest of Poland

• German invasion - On 1 September 1939, Germany launched a sudden and overwhelming attack on Poland using Blitzkrieg tactics, which combined fast-moving armoured units, air support, and infantry to overrun enemy defences quickly.
• Soviet involvement - On 17 September, as part of the secret Molotov-Ribbentrop Pact (a non-aggression agreement between Germany and the Soviet Union signed in August 1939), the Soviet Union invaded Poland from the east, splitting the country between the two powers.
• Partition of Poland - By the end of September, Poland was divided, with Germany annexing the western regions and the Soviet Union taking the east, effectively erasing Poland from the map as an independent state for the duration of the war.

The Phoney War in the West

Following the fall of Poland, from September 1939 to April 1940, there was little military activity on the Western Front between Germany and the Allied powers (Britain and France). This period became known as the "Phoney War" due to the lack of significant engagements. Both sides prepared for future conflicts, with Britain and France expecting a prolonged defensive war, while Germany planned its next moves in Western Europe. This lull created a false sense of security among the Allies.

Key European campaigns (1939–1940)

After the initial conquest of Poland, Axis forces turned their attention to other parts of Europe, targeting strategic territories to consolidate power and weaken Allied resistance. These campaigns demonstrated the effectiveness of German military tactics and exposed vulnerabilities in Allied preparations.

The Winter War: Soviet invasion of Finland

• Soviet aggression - On 30 November 1939, the Soviet Union invaded Finland, seeking territorial gains and a buffer zone against Germany, following the Molotov-Ribbentrop Pact's secret protocols.
• Finnish resistance - Despite being vastly outnumbered, Finland mounted a fierce defence, using the harsh winter terrain to their advantage, inflicting heavy casualties on Soviet forces.
• Soviet victory at high cost - By March 1940, Finland was forced to cede territory in the Peace of Moscow, but the Soviet Union's poor military performance exposed weaknesses, damaging its international reputation and costing thousands of lives.

German invasion of Denmark and Norway

• Strategic objectives - On 9 April 1940, Germany invaded Denmark and Norway to secure access to the North Sea, protect iron ore supplies from Sweden, and establish naval bases for operations against Britain.
• Rapid conquest - Denmark surrendered within hours due to its small military, while Norway resisted for two months with British and French support but ultimately fell to German control, providing the Axis with crucial Atlantic access points.

The Fall of France

• Invasion through the Ardennes - On 10 May 1940, Germany launched a surprise attack through the Ardennes Forest, bypassing the heavily fortified Maginot Line (a series of French defensive fortifications along the German border), catching Allied forces off guard.
• Dunkirk evacuation - As German forces advanced, over 300,000 British and French troops were trapped at Dunkirk but were evacuated between 26 May and 4 June 1940 in a massive rescue operation, preserving a significant portion of Allied manpower.
• French surrender - On 22 June 1940, France signed an armistice, leading to German occupation of the north and west, while the south became Vichy France, a collaborationist regime under Marshal Philippe Pétain.

The Battle of Britain

• Luftwaffe's campaign - From July to October 1940, the German air force (Luftwaffe) attempted to gain air superiority over Britain by bombing airfields, cities, and infrastructure as a prelude to Operation Sealion, the planned invasion of Britain.
• RAF resistance - The Royal Air Force (RAF) Fighter Command, using radar technology and determined pilots, successfully repelled the attacks, inflicting heavy losses on the Luftwaffe despite being outnumbered.
• Abandonment of invasion plans - Hitler postponed Operation Sealion indefinitely in October 1940, marking the first major German defeat and boosting Allied morale, as Britain remained a stronghold against Axis dominance in Western Europe.

Axis expansion in the Mediterranean, North Africa, and the Balkans (1940–1941)

With Western Europe largely under control, the Axis powers sought to expand their influence into southern Europe and North Africa, aiming to secure vital resources and strategic positions. Italy's involvement as an Axis partner introduced new theatres of conflict.

Italy's entry and early failures

In June 1940, Italy, under Benito Mussolini, entered the war on Germany's side, hoping to gain territories in the Mediterranean and Africa. Italian campaigns faltered, with a failed invasion of Greece in October 1940 and significant losses in Libya against British forces, revealing military weaknesses and overambition.

German intervention in southern theatres

• Support in North Africa - Germany deployed the Afrika Korps under General Erwin Rommel in early 1941 to bolster Italian forces in Libya, pushing back British troops and securing key desert territories.
• Balkans campaign - In April 1941, Germany invaded Yugoslavia and Greece to secure the region after Italian setbacks and Yugoslav resistance to Axis pressure, rapidly conquering both areas to protect their southern flank ahead of further operations.

Operation Barbarossa: Invasion of the Soviet Union (1941)

In a dramatic shift of strategy, Germany turned eastwards, breaking its pact with the Soviet Union to launch a massive invasion. This campaign marked a turning point in the war, stretching Axis resources across an enormous front.

Decision and initial successes

• Hitler's gamble - On 22 June 1941, Germany initiated Operation Barbarossa, aiming to conquer the Soviet Union, seize resources like oil and grain, and achieve Hitler's ideological goal of Lebensraum (living space) in the east.
• Rapid advances - German forces achieved stunning early successes, capturing vast territories and encircling Soviet armies, advancing towards key cities like Moscow, Leningrad, and Kyiv with Blitzkrieg tactics.
• Logistical challenges - Despite initial victories, the sheer size of the Soviet Union, harsh weather, and overextended supply lines began to slow German progress, testing their military capacity.

Soviet resistance

• Stiffening defence - Soviet forces, though initially disorganised, regrouped under harsh conditions, using scorched-earth tactics (destroying resources to deny them to the enemy) and mobilising vast reserves of manpower.
• Turning tide near Moscow - By late 1941, Soviet counterattacks, bolstered by the onset of winter, halted the German advance just outside Moscow, marking a critical setback for Operation Barbarossa and preventing a quick victory.

Globalisation of the war and Axis power by late 1941

By the end of 1941, the Second World War had expanded beyond Europe, becoming a truly global conflict with the entry of new major powers. The Axis reached the height of their territorial control during this period, but cracks in their dominance began to appear.

Japan's expansion and American entry

On 7 December 1941, Japan launched a surprise attack on Pearl Harbor, targeting the U.S. naval base in Hawaii. This attack was the culmination of Japan's aggressive expansion throughout 1941 in Asia and the Pacific, as they sought resources and territory. The attack prompted the United States to declare war on Japan, and subsequently on Germany and Italy, transforming the war into a global struggle with the Allies now including a major industrial and military power.

Extent of Axis power by late 1941

• Territorial dominance - By the end of 1941, Axis powers controlled much of Europe (from France to the Soviet border), parts of North Africa, and significant territories in Asia and the Pacific through Japan's conquests.
• Strategic challenges - Despite these gains, the Axis faced mounting challenges: Germany's stalled invasion of the Soviet Union, Britain's resilience, and the entry of the United States signalled the beginning of a shift in momentum towards the Allies.
• Turning points - The failure to defeat Britain, the overextension in the Soviet Union, and the globalisation of the conflict highlighted the limits of Axis expansion, setting the stage for a prolonged and increasingly difficult war.