Free City of Danzig in the context of "Polish Corridor"

The Second Polish Republic, officially known at the time as the Republic of Poland, was a country in Central and Eastern Europe that existed between 7 October 1918 and 6 October 1939 after being established in the final stage of World War I. The Second Republic was taken over in 1939, after it was invaded by Nazi Germany, the Soviet Union, and the Slovak Republic, marking the beginning of the European theatre of the Second World War. The Polish government-in-exile was established in Paris and later London after the fall of France in 1940.

When, after several regional conflicts, most importantly the victorious Polish-Soviet war, the borders of the state were finalized in 1922, Poland's neighbours were Czechoslovakia, Germany, the Free City of Danzig, Lithuania, Latvia, Romania, and the Soviet Union. It had access to the Baltic Sea via a short strip of coastline known as the Polish Corridor on either side of the city of Gdynia. Between March and August 1939, Poland also shared a border with the then-Hungarian governorate of Subcarpathia. In 1938, the Second Republic was the sixth largest country in Europe. According to the 1921 census, the number of inhabitants was 25.7 million. By 1939, just before the outbreak of World War II, this had grown to an estimated 35.1 million. Almost a third of the population came from minority groups: 13.9% Ukrainians; 10% Ashkenazi Jews; 3.1% Belarusians; 2.3% Germans and 3.4% Czechs and Lithuanians. At the same time, a significant number of ethnic Poles lived outside the country's borders.

The Battle of Westerplatte was the first battle of the German invasion of Poland, marking the start of World War II in Europe. It occurred on the Westerplatte peninsula in the harbour of the Free City of Danzig (now Gdańsk, Poland). A small forested island separated from Gdansk by the harbour channel, Westerplatte was established as a Polish military outpost during the interwar period.

In the mid-1920s, the Second Polish Republic established the Polish Military Transit Depot (Wojskowa Składnica Tranzytowa, WST) on the Westerplatte peninsula in the Free City of Danzig. Beginning on 1 September 1939, the German Wehrmacht and Danzig Police assaulted the WST. Despite initial assessment on both sides that the Polish garrison might hold out for several hours before being reinforced or overwhelmed, the Poles held out for seven days and repelled thirteen assaults that included dive-bomber attacks and naval shelling.

Westerplatte (Polish pronunciation: [vɛstɛrˈplatɛ], [ˈvɛstɛrplatɛ], German pronunciation: [ˈvɛstɐplatə]) is a peninsula in Gdańsk, Poland, located on the Baltic Sea coast mouth of the Dead Vistula (one of the Vistula delta estuaries), in the Gdańsk harbour channel. From 1926 to 1939, it was the location of a Polish Military Transit Depot (WST), sanctioned within the territory of the Free City of Danzig (now Gdańsk).

The first shots of the Second World War were fired at the Battle of Westerplatte which began at 0450hrs on the 1 September, 1939. The fighting started when the German WWI battleship SMS Schleswig-Holstein began shelling the Polish ammunition depot on Westerplatte. After a siege that lasted a week, the Polish garrison surrender to German forces that were part of invasion of Poland.

Gdańsk (Kashubian: Gduńsk; German: Danzig) is a city on the Baltic coast of northern Poland, and the capital of the Pomeranian Voivodeship. With a population of 486,492, it is Poland's sixth-largest city and its major seaport. Gdańsk lies at the mouth of the Motława River and is situated at the southern edge of Gdańsk Bay, close to the city of Gdynia and the resort town of Sopot; these form a metropolitan area called the Tricity (Trójmiasto), with a population of approximately 1.5 million.

Gdańsk was first mentioned in 997 as part of the early Polish state, and thereafter grew into a trading town under the Piast and Samboride dynasties. Shifting between Polish and Teutonic control during the Middle Ages, it subsequently joined the Hanseatic League and, with considerable autonomy, served as Poland's principal seaport and largest city until the early 18th century. With the Partitions of Poland, the city was annexed by Prussia in 1793, and was integrated into the German Empire in 1871. It was a free city from 1807 to 1814 and from 1920 to 1939. On 1 September 1939, it was the site of a military clash at Westerplatte, one of the first events of World War II. The contemporary city was shaped by extensive border changes, expulsions and resettlement after 1945. In the 1980s, Gdańsk was the birthplace of the Solidarity trade union and movement, which helped precipitate the collapse of communism in Europe.

Carl Jacob Burckhardt (September 10, 1891 – March 3, 1974) was a Swiss diplomat and historian. His career alternated between periods of academic historical research and diplomatic postings; the most prominent of the latter were League of Nations High Commissioner for the Free City of Danzig (1937–39) and President of the International Committee of the Red Cross (1945–48).

While serving as High Commissioner for Danzig, Burckhardt sought to avoid escalation of tensions between Nazi Germany and Poland into open military conflict. Unlike his predecessor, who had been removed as High Commissioner at Germany's insistence because he sought to protect Danzig's Jewish community, Burckhardt tried to cultivate relations with the "moderate" Nazi leaders of Danzig while blaming the Polish government for taking too uncompromising a stand against German demands that Danzig be returned to Germany. Those efforts, which had reflected the attitudes of the League, the United Kingdom and France, failed with Germany's invasion of Poland and seizure of Danzig on 1 September 1939. Burckhardt fled Danzig after being told by the Nazi Gauleiter for Danzig that he would be executed if he did not.

The Greater Germanic Reich (German: Großgermanisches Reich), fully styled the Greater Germanic Reich of the German Nation (German: Großgermanisches Reich der Deutschen Nation), was the official state name of the political entity that Nazi Germany tried to establish in Europe during World War II. The territorial claims for the Greater Germanic Reich fluctuated over time. As early as the autumn of 1933, Adolf Hitler envisioned annexing such territories as Bohemia, western Poland, and Austria to Germany and the formation of satellite or puppet states without independent economies or policies of their own.

This pan-Germanic Empire was expected to assimilate practically all of Germanic Europe into an enormously expanded Reich. Territorially speaking, this encompassed the already-enlarged German Reich itself (consisting of pre-1938 Germany proper, Austria, Bohemia, Moravia, Czech Silesia, Alsace-Lorraine, Eupen-Malmedy, Memel, Lower Styria, Upper Carniola, Southern Carinthia, Danzig, and Poland), the Netherlands, Belgium, Luxembourg, Denmark, Norway, Sweden, Iceland, Liechtenstein, parts of northern and northeastern France, and the German-speaking and French-speaking parts of Switzerland.

The Province of West Prussia (German: Provinz Westpreußen; Kashubian: Zôpadné Prësë; Polish: Prusy Zachodnie) was a province of Prussia from 1773 to 1829 and from 1878 to 1919. West Prussia was established as a province of the Kingdom of Prussia in 1773, formed from Royal Prussia of the Polish–Lithuanian Commonwealth annexed in the First Partition of Poland. West Prussia was dissolved in 1829 and merged with East Prussia to form the Province of Prussia, but was re-established in 1878 when the merger was reversed and became part of the German Empire. From 1918, West Prussia was a province of the Free State of Prussia within Weimar Germany, losing most of its territory to the Second Polish Republic and the Free City of Danzig in the Treaty of Versailles. West Prussia was dissolved in 1919, and its remaining western territory was merged with Posen to form Posen-West Prussia, and its eastern territory merged with East Prussia as the Region of West Prussia district.

West Prussia's provincial capital alternated between Marienwerder (present-day Kwidzyn, Poland) and Danzig (Gdańsk, Poland) during its early existence. West Prussia was notable for its ethnic and religious diversity due to immigration and cultural changes, with the population becoming mixed over the centuries. Since the early Middle Ages the bulk of the region was inhabited by West Slavic Lechitic tribes (Pomeranians in the Pomerelia region and Masovians in Kulmerland), while the actual Old Prussians (Pomesanians and Pogesanians) populated only the remaining part of the territory lying to the east of the Vistula River. The Teutonic Order's conquest of the region resulted in German colonization in the 14th century. As a result of Germanisation, Germans became in the middle of the 19th century the most numerous ethnic group in West Prussia as a whole, remaining as such until the dissolution of the province in 1920, though their distribution was uneven: their majority was concentrated in Danzig, the western lands of the province, along the Vistula river, and in the Pomesanian and Pogesanian portion of the province located east of the Vistula, with a small admixture of Poles (Gedanians and Powiślans). Meanwhile, Poles (Kociewians, Borowians and Chełminians) as well as Kashubians continued to predominate in parts of Pomerelian territories west of Vistula and in parts of the Chełmno Land, forming altogether around 36% of the population of the province as a whole. There were also sizeable minorities of Mennonites and Jews settling in the region.