Invasion of Poland, 1939

On September 1, 1939, at 4:45 am, the German battleship Schleswig-Holstein attacked the Polish garrison at Westerplatte Fort, Danzig (now Gdańsk). This marked the start of World War II as, simultaneously, 62 German divisions, backed by 1,300 aircraft, began the invasion of Poland.

Adolf Hitler anticipated a swift victory in Poland for two main reasons. He believed the Wehrmacht (German Army) would overpower the Polish military through a blitzkrieg strategy. Moreover, he perceived British and French leaders, Neville Chamberlain and Edouard Daladier, as weak and indecisive, and predicted they would choose peace over conflict.

Hitler’s assessment stemmed from his prior success in revising the Treaty of Versailles, which imposed severe restrictions on Germany following its World War I defeat. Britain and France, adopting a policy of appeasement, permitted German actions violating the Treaty, such as rearmament in 1935, reoccupying the Rhineland in 1936, annexing Austria in 1938, and taking the Sudetenland from Czechoslovakia. These actions, fueled by threats of military aggression, revealed the Western powers’ hesitancy.

Moreover, public opinion in the West viewed the Treaty of Versailles critically and perceived communism as a more significant threat than fascism. Many thus appreciated a stronger Germany to counterbalance the Soviet Union. From 1933-1938, the Western press largely portrayed Hitler positively, underscored by events like the 1936 Berlin Olympics and visits from figures like the Duke of Windsor and David Lloyd George.

However, the landscape shifted in March 1939. Hitler overstepped by occupying all of Czechoslovakia and reclaiming the province of Memel from Lithuania. These actions directly contradicted his previous assurance to Chamberlain that he had no more territorial aspirations in Europe. In response, Chamberlain guaranteed Poland’s borders and urged Hitler to temper his ambitions.

Nonetheless, Hitler pressed on. On April 3, he instructed the Wehrmacht to prepare for a September 1 invasion of Poland. He doubted Chamberlain would defend Poland and believed France wouldn’t act without British support.

Hitler feared that a sudden attack on Poland might provoke Stalin, leading to a war with the Soviet Union. To preempt this, he directed his Foreign Minister, Joachim von Ribbentrop, to discreetly negotiate with the Soviets. This culminated in the Nazi-Soviet Pact on August 23, 1939. The agreement divided Poland between them, while Hitler acknowledged that Latvia, Lithuania, Estonia, Finland, and parts of Romania would be under Soviet influence.

On September 1, German forces attacked Poland from Prussia in the north and Slovakia in the south. Achieving air dominance on day one, they bombed towns causing mass panic among civilians, which hindered Polish reinforcements. Their blitzkrieg strategy prioritized constant movement, not allowing Polish forces to regroup.

On September 1, at 8:00 am, Poland sought help from France and Britain. Only on September 3, at noon, did Britain declare war on Germany, with France following at 5:00 pm. The delay indicated British hopes of Hitler reconsidering the invasion.

The swift invasion caught Western military chiefs off guard. France, having heavily invested in the Maginot line’s static defenses, lacked an offensive strategy, while the British Royal Air Force dropped peace-promoting leaflets instead of bombs.

By September 8, German Panzers neared Warsaw, advancing 140 miles (225 km) in eight days. On September 10, Polish forces retreated to Eastern Poland, hoping for Western allies to intervene.

Yet, despite Marshal Maurice Gamelin’s assurances, all combat actions on the Western front halted on September 13 as French troops retreated to the Maginot line’s safety. By September 15, Warsaw was encircled and endured relentless bombings.

On September 17, the Soviet Union’s Red Army invaded Poland from the east as per the Nazi-Soviet agreement, effectively sealing Poland’s fate. Many Poles who managed to escape fled to Romania, with some eventually joining the Free Polish Forces in the West.

Warsaw, under constant bombardment, capitulated on September 27. Though Germany and the Soviet Union secured a quick win, Britain and France declined Hitler’s peace proposal, and Poland became World War II’s first battleground.

In 1940, the Soviet Union invaded the Baltic states. While they initially faced resistance in the “Winter War” against Finland, they eventually succeeded, annexing parts of eastern Finland. The Soviets also took Bessarabia and northern Bukovina from Romania.