https://www.facebook.com/learnpolishdaily/On this day, on September 1 1939, Germany attacked Poland, which marked the beginning of World War II in Europe. Following several German-staged incidents, the first regular act of war took place on 1 September 1939, at 04:40, when the German airforce Luftwaffe attacked the Polish town of Wieluń, destroying 75% of the city and killing close to 1,200 people, most of them civilians.
Five minutes later, German battleship Schleswig-Holstein opened fire on the Polish military transit depot at Westerplatte in the Free City of Danzig (Wolne Miasto Gdańsk) on the Baltic Sea. German naval forces and soldiers and Danzig police assaulted the Polish Military Transit Depot (Wojskowa Składnica Tranzytowa, or WST) on the peninsula of Westerplatte, in the harbour of the Free City of Danzig. The Poles held out for seven days in the face of a heavy attack that included dive bomber attacks. The defense of Westerplatte served as an inspiration for the Polish Army and people in the face of successful German advances elsewhere, and today is still regarded as a symbol of resistance to the invasion.
On 17 September 1939, 16 days after Germany invaded Poland from the west, the Soviet Union invaded Poland from the east. The invasion and the battle lasted for the following 20 days and ended on 6 October 1939 with the two-way division and annexation of the entire territory of the Second Polish Republic by both Germany and the Soviet Union. The joint German-Soviet invasion of Poland was secretly agreed to in the Molotov-Ribbentrop Pact, signed on 23 August 1939.
The Defence of the Polish Post Office in Danzig (Gdańsk) was also one of the first acts of German invasion. On September 1, 1939, Polish personnel defended the building for some 15 hours against assaults by the SS Heimwehr Danzig (SS Danzig Home Defense), local SA formations and special units of Danzig police. All but four of the defenders, who were able to escape from the building during the surrender, were sentenced to death by a German court martial as illegal combatants on October 5, 1939 and executed.
At 08:00, German troops—still without a formal declaration of war issued—attacked near the Polish town of Mokra. The Battle of the Border had begun. Later that day, the Germans attacked on Poland's western, southern and northern borders, while German aircraft began raids on Polish cities. The main axis of attack led eastwards from Germany proper through the western Polish border. Supporting attacks came from East Prussia in the north, and a co-operative German-Slovak tertiary attack by units (Field Army "Bernolák") from German-allied Slovakia in the south. All three assaults converged on the Polish capital of Warsaw.
The Allied governments declared war on Germany on 3 September; however, they failed to provide any meaningful support. The German-French border saw only a few minor skirmishes, although the majority of German forces, including 85% of their armoured forces, were engaged in Poland. Despite some Polish successes in minor border battles, German technical, operational and numerical superiority forced the Polish armies to retreat from the borders towards Warsaw and Lwów.
The Luftwaffe, German aerial warfare, gained air superiority early in the campaign. By destroying communications, the Luftwaffe increased the pace of the advance which overran Polish airstrips and early warning sites, causing logistical problems for the Poles. Many Polish Air Force units ran low on supplies, 98 of their number withdrew into then-neutral Romania. The Polish initial strength of 400 was reduced to just 54 by 14 September and air opposition virtually ceased.
The largest battle during this campaign—the Battle of Bzura—took place near the Bzura river west of Warsaw and lasted 9–19 September. Polish armies Poznań and Pomorze, retreating from the border area of the Polish Corridor, attacked the flank of the advancing German 8th Army, but the counterattack failed after initial success. After the defeat, Poland lost its ability to take the initiative and counterattack on a large scale.