A Free City under the protection of the League of Nations from 1920, Danzig became the crux of the Polish–German dispute in 1939. On 1 September the Germans attacked Westerplatte and the Polish Post Office there, Albert Forster proclaimed the city's annexation to the Reich, and the Gestapo, police and SS began arresting Poles. On 30 March 1945 Soviet troops supported by the Polish 1st Armoured Brigade took Gdańsk; its Main Town lay in ruins.
1920
1939
- 21 March 1939EventGerman demands on PolandOn 21 March 1939 Ribbentrop renewed to Ambassador Lipski the demand for Danzig and an extraterritorial route across Pomerania, now under time pressure.
- 10 July 1939EventChamberlain on DanzigOn 10 July 1939 Chamberlain told the House of Commons that an attempt to seize Danzig threatening Polish independence would trigger the British guarantee.
- 1 September 1939EventGermany annexes the Free City of DanzigOn 1 September 1939 Albert Forster proclaimed the Free City of Danzig part of the Reich, and the Reichstag confirmed it by law. Arrests of Poles began.
- 1 September 1939EventThe defence of the Polish Post Office in GdańskOn 1 September 1939 Polish postal workers held the Polish Post Office in Gdańsk for about 14 hours. After their surrender 38 were sentenced to death and shot.
- 1 September 1939EventThe defence of Westerplatte beginsAt 4.45 a.m. on 1 September 1939 the battleship Schleswig-Holstein shelled the Polish depot on Westerplatte. Its garrison beat off two assaults that day.
- 1 September – 6 October 1939BattleInvasion of PolandFrom 1 September to 6 October 1939 Poland fought Nazi Germany, Slovakia and, from 17 September, the Soviet Union. The campaign ended in partition.
- 1–7 September 1939BattleBattle of WesterplatteFrom 1 to 7 September 1939 some 200 Polish soldiers held the Westerplatte depot against a battleship, naval infantry, Danzig police and Stukas.
1945
- 10 February – 4 April 1945BattleEast Pomeranian offensiveIn February–April 1945 two Soviet fronts and the Polish 1st Army routed the Germans in Pomerania, reached the Baltic and took Kołobrzeg, Gdynia and Gdańsk.
- 30 March 1945EventThe capture of DanzigOn 30 March 1945 the 2nd Belorussian Front and Polish tank crews took Gdańsk. The Main Town lay in ruins, much of it burned after the fighting had ended.