Following World War I, the formerly German port of Danzig (modern-day Gdansk, Poland) was made a “free city,” separated from Germany by a sliver of Polish territory. Adolf Hitler manufactured a conflict with Poland over this anomalous situation as a pretext for invading 80 years ago Sunday. Colin Shindler describes the situation of the city’s Jews at the time:

After the upheavals of the World War I, Danzig had become a temporary location for stateless and persecuted Jews, seeking a better life elsewhere. Many were encamped in a special transit facility on the city’s outskirts where they were helped by Danzig’s Jewish community. In the 1920s, some 60,000 homeless Jews passed through.

The Nazi virus, after infecting Weimar Germany, was soon exported to Danzig’s German citizens. . . . In May 1933, the Nazis won power in Danzig through a democratic election. . . . One tactic used by the Nazis was to create a split between the acculturated German-Jewish leadership and the [more] traditional Ostjuden from Poland. [Yet they refused] to denounce each other. Even so, by 1937, 3,000 Jews had left.

In October 1937, the local Nazis announced that they could not guarantee the rights of foreign-born Jews. A year later, Kristallnacht resulted in the burning down of two synagogues and the desecration of two others. . . . On January 2, 1939, laws excluding Jews from economic life and the professions came into force in Danzig. Deportations began shortly afterward.

When war broke out on September 1, German troops seized Danzig in a matter of hours:

The following day, the Nazis established the first concentration camp outside German borders at Stutthof, 30 miles from Danzig. It was also the last camp to be liberated by the Allies, on May 9, 1945. Over 60,000 died there in the intervening period—half of them Jews.