The Free City of Danzig was established in 1920 pursuant to the resolutions of the Treaty of Versailles signed a year earlier. A territory of 1952 km2 was inhabited by approx. 350 thousand residents in 1920, 407 thousand residents in 1933 and 388 thousand residents in 1939, most of whom were Germans (or more specific: germanspeaking Citizens of Danzig). Poles made (according to various estimates) 9% to 13% of the population of the Free City of Danzig. The other ethnic groups (Jewish, Ukrainian, Russian and others) made a small percent of the population.
The Free City of Danzig was a compromise between the German nature of the city on one hand and the economic arguments (related to making the seaport accessible to the reborn Poland) on the other hand, which was a source of persistent tensions between Warsaw and Berlin during the interwar period. At the end of the thirties, the demands to incorporate Danzig into the Reich became one of the pretexts for the German-Polish relations to aggravate. It was actually Danzig where, on September 1, 1939, the German warship ”Schleswig-Holstein” opened cannon fire at the Polish outpost on the Westerplatte Peninsula, thus starting the Second World War.
The Free City of Danzig had its own anthem, flag, crest and also, since 1924, its currency (the Danzig gulden). In spite of appearances, it was not a state under the international law, it was not an independent state entity – it was made dependent on the League of Nations and on Poland. The German party also had a significant, indirect influence on the situation in Danzig. As a result, there were as many as four centres of authority in the territory of the Free City: the Danzig centre (a single-chamber parliament – Volkstag and the highest executive authority – the Senate presided by the Senate President), the High Commissioner of the League of Nations (a representative of the League of Nations which was a guarantor of the constitution and status of the Free City of Danzig), the General Commissioner of the Republic of Poland (a representative of the interests of Poland) and the Council of Waterways and Port (theoretically an autonomous authority administering the port of Danzig and Vistula within the Free City).
- Formation, development and activity of NSDAP and its organisation in the Free City of Danzig, particularly SA and SS
- Danzig police
- History of the individual districts and estates (especially Wrzeszcz / Langfuhr)
- Emigrants from the Free City of Danzig
- Academic fraternities in the Free City of Danzig
- The Free City of Danzig in the Polish-German interwar relationships
- Sport, physical culture and tourism
- Position of the Free City of Danzig in the historical remembrance