The 75th Anniversary of Germany’s Invasion of Poland

By Michael Fry
Senior Map Librarian, National Geographic Library

For many armchair historians, Nazi Germany’s invasion of Poland evokes powerful imagery: waves of German infantry pouring into Poland; the Luftwaffe’s shrieking Stuka dive bombers; Panzer divisions streaking across the Polish plain.

Germany’s blitzkrieg tactic was indeed impressive—Adolf Hitler had modernized Germany’s military more quickly than his European adversaries had theirs, and the results were according to plan. The invasion, aided as it was by clear weather and the forgiving Polish terrain, brought Poland’s outmoded defense to its knees in just a few days’ time.

The first shots of World War II, however, were fired at a target that may have been more symbolic than strategic. That target was Danzig, an ethnically German city located northwest of Warsaw on the Baltic Sea coast that had been part of Germany from the early 1800’s until the end of World War I.

Hitler’s interest in Danzig was long-standing. Indeed, it was central to the Nazi ideology, which called for the unification of all German people. Danzig had been stripped from German control after World War I and established as the Free City of Danzig under League of Nations authority. Germany had also lost portions of Posen and West Prussia provinces, which had been ceded to to the newly reconstituted nation of Poland.

Danzig and the so-called Polish Corridor ensured Poland’s access to the Baltic Sea, but they also separated East Prussia from the rest of Germany. This outraged many Germans, who were embittered by their defeat in World War I and infuriated that the Treaty of Versailles had forced them to surrender territory. According to William Shirer’s classic history Rise and Fall of the Third Reich, “To [Germans] the most heinous crime of the Versailles peacemakers had been to separate East Prussia from the Reich by the Polish Corridor, to detach Danzig and to give to the Poles the province of Posen…”

Like many Germans, Hitler considered Danzig’s status temporary. Throughout the 1930s, Hitler called for Danzig be reunited with Germany. He also wanted German-controlled transportation lines to be built across the corridor in order to connect East Prussia with the rest of Germany.  In January 1939, he told Polish Foreign Minister Josef Beck, “Danzig was German, would always remain German, and sooner or later would return to Germany.”

Poland, responsible for Danzig’s defense and foreign relations, repeatedly rejected these demands. Once assured that hostilities with Poland wouldn’t put Germany at odds with the Soviet Union, Hitler abandoned his pretense of trying to negotiate a peaceful settlement to the “Polish Problem” and attacked.

At approximately 4:45 a.m. on September 1, 1939, Germany began a massive invasion of Poland. The first shots—fired at Danzig—came not from one of Hitler’s modern weapons of war, but from the SMS Schleswig-Holstein, a three-decades-old German battleship on a “good will” visit to Danzig’s harbor. By shelling a Polish ammunition depot located on Danzig’s Westerplatte peninsula, the Schleswig-Holstein started the 7-day Battle of Westerplatte and, thus, World War II.

The Poles on Westerplatte inflicted disproportionately heavy losses on their aggressors, but Danzig (today the Polish city of Gdańsk) and the Polish Corridor were soon overrun—and annexed—by the Third Reich.