The Invasion of Poland, also known as the September Campaign or 1939 Defensive War (Polish: Kampania wrześniowa or Wojna obronna 1939 roku) in Poland and the Poland Campaign (German: Polenfeldzug) in Germany, was an invasion of Poland by Nazi Germany, the Soviet Union, and a small Slovak contingent that marked the start of World War II. The invasion began on 1 September 1939, one week after the signing of the Molotov–Ribbentrop Pact, and ended 6 October 1939 with Germany and the Soviet Union dividing and annexing the whole of Poland.
The day after the Gleiwitz incident, German forces invaded Poland from the north, south, and west. As the Germans advanced, Polish forces withdrew from their forward bases of operation close to the Polish-German border to more established lines of defence to the east. After the mid-September Polish defeat in the Battle of the Bzura, the Germans gained an undisputed advantage. Polish forces then withdrew to the southeast where they prepared for a long defence of the Romanian Bridgehead and awaited expected French and British support and relief.
The Soviet Red Army's invasion of the Kresy on 17 September, in accordance with a secret protocol of the Molotov–Ribbentrop Pact, rendered the Polish plan of defence obsolete. Facing a second front, the Polish government concluded the defence of the Romanian Bridgehead was no longer feasible and ordered an emergency evacuation of all troops to neutral Romania. On 6 October, following the Polish defeat at the Battle of Kock, German and Soviet Union forces gained full control over Poland. The success of the invasion marked the end of the Second Polish Republic, though Poland never formally surrendered.
On 8 October, Germany directly annexed western Poland and the former Free City of Danzig and placed the remaining block of territory under administration of the newly established General Government. The Soviet Union immediately started a campaign of sovietization of the newly acquired areas. This included staged elections, the results of which were used to legitimize the Soviet Union's annexation of eastern Poland. In the aftermath of the invasion, a collective of underground resistance organizations formed the Polish Underground State within the territory of the former Polish state. Many of the military exiles that managed to escape Poland subsequently joined the Polish Armed Forces in the West, an armed force loyal to the Polish government in exile.
In 1933, the National-Socialist German Workers' Party, under their leader Adolf Hitler, came to power in Germany. Germany sought to gain hegemony in Europe, and to take over Soviet Union territory, acquiring "Living Space" (Lebensraum) and expanding "Greater Germany" (Großdeutschland), to be eventually surrounded by a ring of allied states, satellite or puppet states. As part of this long term policy, at first, Hitler pursued a policy of rapprochement with Poland, trying to improve German–Polish relations, culminating in the German–Polish Non-Aggression Pact of 1934. Earlier, Hitler's foreign policy worked to weaken the ties between Poland and France, and to manoeuvre Poland into the Anti-Comintern Pact, forming a cooperative front against the Soviet Union. Poland would be granted territory of its own, to its northeast, but the concessions the Poles were expected to make meant that their homeland would become largely dependent on Germany, functioning as little more than a client state. The Poles feared that their independence would eventually be threatened altogether.
In addition to Soviet territory, the National-Socialists were also interested in establishing a new border with Poland because the German exclave of East Prussia was separated from the rest of the Reich by the "Polish Corridor". The Corridor constituted land long disputed by Poland and Germany, and inhabited by both groups. The Corridor became a part of Poland after the Treaty of Versailles. Many Germans also wanted the city of Danzig and its environs (together the Free City of Danzig) to be reincorporated into Germany. Danzig was an important port city with more than 95% of the population German speakers. It had been separated from Germany after Versailles and made into a nominally independent Free City of Danzig. Hitler sought to reverse these territorial losses, and on many occasions made an appeal to German nationalism, promising to "liberate" the German minority still in the Corridor, as well as Danzig.
Poland participated in the partition of Czechoslovakia that followed the Munich Agreement, although they were not part of the agreement. It coerced Czechoslovakia to surrender the city of Český Těšín by issuing an ultimatum to that effect on 30 September 1938, which was accepted by Czechoslovakia on 1 October.
By 1937, Germany began to increase its demands for Danzig, while proposing that a roadway be built in order to connect East Prussia with Germany proper, running through the Polish Corridor. Poland rejected this proposal, fearing that after accepting these demands, it would become increasingly subject to the will of Germany and eventually lose its independence as the Czechs had. Polish leaders also distrusted Hitler Furthermore, Germany's collaboration with anti-Polish Ukrainian nationalists from the Organization of Ukrainian Nationalists, which was seen as an effort to isolate and weaken Poland, weakened Hitler's credibility from the Polish point of view. The British were also aware of the situation between Germany and Poland. On 31 March, Poland was backed by a guarantee from Britain and France which stated that Polish territorial integrity would be defended with their support. On the other hand, British Prime Minister Neville Chamberlain and his Foreign Secretary, Lord Halifax, still hoped to strike a deal with Hitler regarding Danzig (and possibly the Polish Corridor), and Hitler hoped for the same. Chamberlain and his supporters believed war could be avoided and hoped Germany would agree to leave the rest of Poland alone. German hegemony over Central Europe was also at stake.
With tensions mounting, Germany turned to aggressive diplomacy as well. On 28 April 1939, it unilaterally withdrew from both the German-Polish Non-Aggression Pact of 1934 and the London Naval Agreement of 1935. Nevertheless, talks over Danzig and the Corridor broke down and months passed without diplomatic interaction between Germany and Poland. During this interim, the Germans learned that France and Britain had failed to secure an alliance with the Soviet Union against Germany and the Soviet Union was interested in an alliance with Germany against Poland. Hitler had already issued orders to prepare for a possible "solution of the Polish problem by military means" - a Case White scenario.
However, with the surprise signing of the Molotov-Ribbentrop Pact on 23 August, the denouement of secret Nazi-Soviet talks held in Moscow, Germany neutralized the possibility of Soviet opposition to a campaign against Poland and war became imminent. In fact, the Soviets agreed to aid Germany in the event of France or the United Kingdom going to war with Germany over Poland and, in a secret protocol of the pact, the Germans and the Soviets agreed to divide Eastern Europe, including Poland, into two spheres of influence; the western third of the country was to go to Germany and the eastern two-thirds to the Soviet Union.
According to the Armenian quote, on 22 August 1939, the day before the signing of the pact, Hitler gathered the Wehrmacht generals and explained his view of the upcoming war:
Our strength is our speed and our brutality. Genghis Khan chased millions of women and children to death, consciously and with a happy heart. History sees him only as a great founder of states. It is of no concern, what the weak Western European civilisation is saying about me. I issued the command - and I will have everybody executed, who will only utter a single word of criticism - that it is not the aim of the war to reach particular lines, but to physically annihilate the enemy. Therefore I have mobilised my Skull Squads, for the time being only in the East, with the command to unpityingly and mercilessly send men, women and children of Polish descent and language to death. This is the only way to gain the Lebensraum, which we need. Who is still talking today about the extinction of the Armenians?"
The German assault was originally scheduled to begin at 04:00 on 26 August. However, on 25 August the Polish-British Common Defence Pact was signed as an annex to the Franco-Polish Military Alliance. In this accord, Britain committed itself to the defence of Poland, guaranteeing to preserve Polish independence. At the same time, the British and the Poles were hinting to Berlin that they were willing to resume discussions – not at all how Hitler hoped to frame the conflict. Thus, he wavered and postponed his attack until 1 September, managing to in effect halt the entire invasion "in mid-leap".
However, there was one exception: in the night of 25/26 August, a German sabotage group which had not heard anything about a delay of the invasion made an attack on the Jablunkov Pass and Mosty railway station in Silesia. In the morning of 26 August this group was repelled by Polish troops. The German side described all this as an incident "caused by an insane individual".(see Jabłonków Incident)
On 26 August Hitler tried to dissuade the British and the French from interfering in the upcoming conflict, even pledging that the Wehrmacht forces would be made available to Britain's empire in the future. The negotiations convinced Hitler that there was little chance the Western Allies would declare war on Germany, and even if they did, because of the lack of territorial guarantees to Poland, they would be willing to negotiate a compromise favourable to Germany after its conquest of Poland. Meanwhile, the number of increased overflights by high-altitude reconnaissance aircraft and cross border troop movements signalled that war was imminent.
On 29 August prompted by the British, Germany issued one last diplomatic offer, with Case White yet to be rescheduled. At midnight on 29 August German Foreign Minister Joachim von Ribbentrop handed British Ambassador Sir Neville Henderson the list of terms which would allegedly ensure peace in regards to Poland. Danzig was to be returned to Germany (Gdynia would remain with Poland), and there was to be a plebiscite in the Polish Corridor, based on residency in 1919, within the year. An exchange of minority populations between the two countries was proposed. A Polish plenipotentiary was to arrive in Berlin and accept these terms by noon the next day. The British Cabinet viewed the terms as "reasonable", except the demand for the urgent plenipotentiary as a form of an ultimatum. When Polish Ambassador Lipski went to see Ribbentrop on 30 August he announced that he did not have the full power to sign, and Ribbentrop dismissed him. It was then broadcast that Poland had rejected Germany's offer, and negotiations with Poland came to an end.
On 29 August German saboteurs planted a bomb at the railway station in Tarnów on 29 August, and killed 21 passengers, leaving 35 wounded.
On 30 August the Polish Navy sent its destroyer flotilla to Britain, executing Operation Peking. On the same day, Marshal of Poland Edward Rydz-Śmigły announced the mobilization of Polish troops. However, he was pressured into revoking the order by the French, who apparently still hoped for a diplomatic settlement, failing to realize that the Germans were fully mobilized and concentrated at the Polish border. During the night of 31 August the Gleiwitz incident, a false flag attack on the radio station, was staged near the border city of Gleiwitz by German units posing as Polish troops, in Upper Silesia as part of the wider Operation Himmler. On 31 August 1939, Hitler ordered hostilities against Poland to start at 4:45 the next morning. Because of the prior stoppage, Poland managed to mobilize only 70% of its planned forces, and many units were still forming or moving to their designated frontline positions.
Poland was attacked by German, Slovak and Russian forces.
Germany had a substantial numerical advantage over Poland and had developed a significant military prior to the conflict. The Heer (army) had some 2,400 tanks organized into six panzer divisions, utilizing a new operational doctrine. It held that these divisions should act in coordination with other elements of the military, punching holes in the enemy line and isolating selected units, which would be encircled and destroyed. This would be followed up by less-mobile mechanized infantry and foot soldiers. The Luftwaffe (air force) provided both tactical and strategic air power, particularly dive bombers that disrupted lines of supply and communications. Together, the so-called "new" methods, were nicknamed "Blitzkrieg" (lightning war). Historian Basil Liddell Hart claimed "Poland was a full demonstration of the Blitzkrieg theory." Other historians, however, disagree.
Aircraft played a major role in the campaign. Bombers also attacked cities, causing huge losses amongst the civilian population through terror bombing. The Luftwaffe forces consisted of 1,180 fighter aircraft: 290 Ju 87 Stuka dive bombers, 1,100 conventional bombers (mainly He 111s and Dornier Do 17s), and an assortment of 550 transport and 350 reconnaissance aircraft. In total, Germany had close to 4,000 aircraft, most of them modern. A force of 2,315 aircraft were assigned to Weiss. Due to its prior participation in the Spanish Civil War, the Luftwaffe was probably the most experienced, best trained and best equipped air force in the world in 1939.
Between 1936 and 1939, Poland invested heavily in the Central Industrial Region. Preparations for a defensive war with Germany were ongoing for many years, but most plans assumed fighting would not begin before 1942. To raise funds for industrial development, Poland sold much of the modern equipment it produced. In 1936, a National Defence Fund was set up to collect funds necessary for strengthening the Polish Armed forces. The Polish Army had approximately a million soldiers, but less than half of them were mobilized by 1 September. Latecomers sustained significant casualties when public transport became targets of the Luftwaffe. The Polish military had fewer armoured forces than the Germans, and these units, dispersed within the infantry, were unable to effectively engage the enemy.
Experiences in the Polish-Soviet War shaped Polish Army organizational and operational doctrine. Unlike the trench warfare of the First World War, the Polish-Soviet War was a conflict in which the cavalry's mobility played a decisive role. . Poland acknowledged the benefits of mobility but was unable to invest heavily in many of the expensive, unproven inventions since then. In spite of this, Polish cavalry brigades were used as a mobile mounted infantry and had some successes against both German infantry and cavalry.
The Polish Air Force (Lotnictwo Wojskowe) was at a severe disadvantage against the German Luftwaffe, although it was not destroyed on the ground early on, as is commonly believed. The Polish Air Force lacked modern fighter aircraft, but its pilots were among the world's best trained, as proven a year later in the Battle of Britain, in which the Poles played a major part.
Overall, the Germans enjoyed numerical and qualitative aircraft superiority. Poland had only about 600 modern aircraft. The Polish Air Force had roughly 185 PZL P.11 and some 95 PZL P.7 fighters, 175 PZL.23 Karaś B, 35 Karaś A, and by September, over 100 PZL.37 Łoś were produced.[Note 5] There were also over a thousand obsolete transport, reconnaissance and training aircraft. However, for the September Campaign, only some 70% of those aircraft were mobilized. Only 36 PZL.37 Łoś bombers were deployed. All those aircraft were of indigenous Polish design, with the bombers being more modern than fighters, according to the Ludomił Rayski air force expansion plan, which relied on a strong bomber force. The Polish fighters were a generation older than their German counterparts. The Polish PZL P.11 fighter, produced in the early 1930s, was capable of only 365 km/h (approximately 220 mi/h), far less than German bombers; to compensate, the pilots relied on its manoeuvrability and high diving speed.
The tank force consisted of two armoured brigades, four independent tank battalions and some 30 companies of TKS tankettes attached to infantry divisions and cavalry brigades.  A standard tank of the Polish Army during the Polish Defensive War of 1939 was 7TP light tank. It was the first tank in the world with diesel engine and 360-degree Gundlach periscope.. 7TP was significantly better armed than its most common opponents, the German Panzer I and Panzer II but only 140 tanks were produced between 1935 and the outbreak of the war. Poland had also a few relatively modern imported designs, such as 50 Renault R35 tanks and 38 Vickers E tanks.
The Polish Navy was a small fleet of destroyers, submarines and smaller support vessels. Most Polish surface units followed Operation Peking, leaving Polish ports on 20 August and escaping by way of the North Sea to join with the British Royal Navy. Submarine forces participated in Operation Worek, with the goal of engaging and damaging German shipping in the Baltic Sea, but they had much less success. In addition, many merchant marine ships joined the British merchant fleet and took part in wartime convoys.
The German plan for what became known as the September Campaign was devised by General Franz Halder, chief of the general staff, and directed by General Walther von Brauchitsch, the commander in chief of the upcoming campaign. It called for the start of hostilities before a declaration of war, and pursued a doctrine of mass encirclement and destruction of enemy forces. The infantry – far from completely mechanized but fitted with fast moving artillery and logistic support – was to be supported by German tanks and small numbers of truck-mounted infantry (the Schützen regiments, forerunners of the panzergrenadiers) to assist the rapid movement of troops and concentrate on localized parts of the enemy front, eventually isolating segments of the enemy, surrounding, and destroying them. The pre-war armored idea (which an American journalist in 1939 dubbed Blitzkrieg), which was advocated by some generals, including Heinz Guderian, would have had the armor punching holes in the enemy's front and ranging deep into rear areas, but in actuality, the campaign in Poland would be fought along more traditional lines. This stemmed from conservatism on the part of the German high command, who mainly restricted the role of armor and mechanized forces to supporting the conventional infantry divisions.
Poland's terrain was well suited for mobile operations when the weather cooperated – the country had flat plains with long frontiers totalling almost 5,600 kilometres (3,500 mi), Poland's long border with Germany on the west and north (facing East Prussia) extended 2,000 kilometres (1,250 mi). Those had been lengthened by another 300 kilometres (180 mi) on the southern side in the aftermath of the Munich Agreement of 1938; the German incorporation of Bohemia and Moravia and creation of the German puppet state of Slovakia meant that Poland's southern flank was exposed.
German planners intended to fully exploit their long border with the great enveloping manoeuvre of Fall Weiss. German units were to invade Poland from three directions:
All three assaults were to converge on Warsaw, while the main Polish army was to be encircled and destroyed west of the Vistula. Fall Weiss was initiated on 1 September 1939, and was the first operation of the Second World War in Europe.
The Polish political determination to deploy forces directly at the German-Polish border, based on the British Government's promise to come to Poland's aid in the event of invasion, shaped the country's defence plan, Plan West. Poland's most valuable natural resources, industry and population were located along the western border in Eastern Upper Silesia. Polish policy centred on their protection especially since many politicians feared that if Poland were to retreat from the regions disputed by Germany, Britain and France would sign a separate peace treaty with Germany similar to the Munich Agreement of 1938. The fact that none of Poland's allies had specifically guaranteed Polish borders or territorial integrity certainly did not help in easing Polish concerns. For these reasons, Poland disregarded French advice to deploy the bulk of their forces behind the natural barriers such as the Vistula and San rivers, even though some Polish generals supported it as a better strategy. The West Plan did permit the Polish armies to retreat inside the country, but it was supposed to be a slow retreat behind prepared positions and was intended to give the armed forces time to complete its mobilization and execute a general counteroffensive with the support of the Western Allies.
The British and French estimated that Poland should be able to defend itself for two to three months, while Poland estimated it could do so for at least six months. Poland drafted its estimates based upon the expectation that the Western Allies honor their treaty obligations and quickly start an offensive of their own. In addition, the French and British expected the war to develop into trench warfare much like World War I. The Polish government was not notified of this strategy and based all of its defence plans on promises of quick relief by their Western allies.
Polish forces were stretched thinly along the Polish-German border and lacked compact defence lines and good defence positions along disadvantageous terrain. This strategy also left supply lines poorly protected. Approximately one-third of Poland's forces were concentrated in or near the Polish Corridor, leaving them perilously exposed to a double envelopment from East Prussia and the west. Another third were massed in the north-central part of the country, between the major cities of Łódź and Warsaw. The Poles' forward concentration largely forfeited their chance of fighting a series of delaying actions since their army, unlike some of Germany's, traveled largely on foot and lacked the ability to retreat to their defensive positions before being overrun by German mechanized formations.
As the prospect of conflict increased, the British government pressed Marshal Edward Rydz-Śmigły, to evacuate the most modern elements of the Polish Navy from the Baltic Sea. In the event of war the Polish military leaders realized that the ships which remained in the Baltic were likely to be quickly sunk by the Germans. Furthermore, the Danish straits were well within operating range of the German Kriegsmarine and Luftwaffe, so there was little chance of an evacuation plan succeeding if implemented after hostilities began. Four days after the signing of the Polish-British Common Defence Pact, three destroyers of the Polish Navy executed the Peking Plan and consequently evacuate to Great Britain.
Although the Polish military had prepared for conflict, the civilian population remained largely unprepared. Polish pre-war propaganda emphasized that that any German invasion would be easily repelled. Consequently, Polish defeats during the German invasion came as a shock to the civilian population, who were largely unprepared. Lacking training for such a disaster the civilian population panicked and retreated east, spreading chaos, lowering troop morale and making road transportation for Polish troops very difficult.
Following several German-staged incidents (like the Gleiwitz incident, a part of Operation Himmler), which German propaganda used as an excuse to claim that German forces were acting in self-defence, the first regular act of war took place on 1 September 1939, at 04:40, when the German Air Force (Luftwaffe) attacked the Polish town of Wieluń, destroying 75% of the city and killing close to 1,200 people, most of them civilians. This invasion subsequently began the Second World War. Five minutes later, the old German battleship Schleswig-Holstein opened fire on the Polish military transit depot at Westerplatte in the Free City of Danzig on the Baltic Sea. 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 axes 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 eighty-five percent 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 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 and 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.
By 3 September when Günther von Kluge in the north had reached the Vistula (some 10 kilometres from the German border at that time) river and Georg von Küchler was approaching the Narew River, Walther von Reichenau's armour was already beyond the Warta river; two days later, his left wing was well to the rear of Łódź and his right wing at the town of Kielce; and by 8 September one of his armoured corps was on the outskirts of Warsaw, having advanced 225 kilometres (140 miles) in the first week of war. Light divisions on Reichenau's right were on the Vistula between Warsaw and the town of Sandomierz by 9 September while List, in the south, was on the river San above and below the town of Przemyśl. At the same time, Guderian led his 3rd Army tanks across the Narew, attacking the line of the Bug River, already encircling Warsaw. All the German armies made progress in fulfilling their parts of the Fall Weiss plan. The Polish armies were splitting up into uncoordinated fragments, some of which were retreating while others were launching disjointed attacks on the nearest German columns.
Polish forces abandoned the regions of Pomerelia (the Polish Corridor), Greater Poland and Polish Upper Silesia in the first week. The Polish plan for border defence was proven a dismal failure. The German advance as a whole was not slowed. On 10 September the Polish commander-in-chief, Marshal Edward Rydz-Śmigły, ordered a general retreat to the southeast, towards the so-called Romanian Bridgehead. Meanwhile, the Germans were tightening their encirclement of the Polish forces west of the Vistula (in the Łódź area and, still farther west, around Poznań) and also penetrating deeply into eastern Poland. Warsaw, under heavy aerial bombardment since the first hours of the war, was attacked on 9 September and was put under siege on 13 September. Around that time, advanced German forces also reached the city of Lwów, a major metropolis in eastern Poland. 1,150 German aircraft bombed Warsaw on 24 September.
The largest battle during this campaign, the Battle of Bzura, took place near the Bzura river west of Warsaw and lasted from 9 September to 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. German air power was instrumental during the battle. The Luftwaffe's offensive broke what remained of Polish resistance in an "awesome demonstration of air power". The Luftwaffe quickly destroyed the bridges across the Bzura River. Afterward, the Polish forces were trapped out in the open, and were attacked by wave after wave of Stukas, dropping 50 kg "light bombs" which caused huge numbers of casualties. The Polish flak positions ran out of ammunition and retreated to the forests, but were then "smoked out" by the Heinkel He 111 and Dornier Do 17s dropping 100 kg incendiaries. The Luftwaffe left the army with the easy task of mopping up survivors. The Stukageschwaders alone dropped 388 tonnes of bombs during this battle.
The Polish government (of President Ignacy Mościcki) and the high command (of Marshal Edward Rydz-Śmigły) left Warsaw in the first days of the campaign and headed southeast, reaching Lublin on 6 September. From there it moved on 9 September to Kremenez, and on 13 September to Zaleshiki on the Romanian border. Rydz-Śmigły ordered the Polish forces to retreat in the same direction, behind the Vistula and San rivers, beginning the preparations for the long defence of the Romanian Bridgehead area.
From the beginning, the German government repeatedly asked Vyacheslav Molotov whether the Soviet Union would keep to its side of the partition bargain. Soviet forces attacked Poland on 17 September. It was agreed that the USSR would relinquish its interest in the territories between the new border and Warsaw in exchange for inclusion of Lithuania in the Soviet "zone of interest".
By 17 September 1939, the Polish defense was already broken and the only hope was to retreat and reorganize along the Romanian Bridgehead. However, these plans were rendered obsolete nearly overnight, when the over 800,000 strong Soviet Union Red Army entered and created the Belarussian and Ukrainian fronts after invading the eastern regions of Poland in violation of the Riga Peace Treaty, the Soviet-Polish Non-Aggression Pact, and other international treaties, both bilateral and multilateral.[Note 6] Soviet diplomacy claimed that they were "protecting the Ukrainian and Belarusian minorities of eastern Poland since the Polish government had abandoned the country and the Polish state ceased to exist".
Polish border defence forces in the east, known as the Korpus Ochrony Pogranicza, consisted of about 25 battalions. Edward Rydz-Śmigły ordered them to fall back and not engage the Soviets. This, however, did not prevent some clashes and small battles, such as the Battle of Grodno, as soldiers and local population attempted to defend the city. The Soviets murdered numerous Polish officers, including prisoners of war like General Józef Olszyna-Wilczyński. The Organization of Ukrainian Nationalists rose against the Poles, and communist partisans organized local revolts, robbing and murdering Poles. Those movements were quickly disciplined by the NKVD. The Soviet invasion was one of the decisive factors that convinced the Polish government that the war in Poland was lost. Prior to the Soviet attack from the east, the Polish military's fall-back plan had called for long-term defence against Germany in the southern-eastern part of Poland, while awaiting relief from a Western Allies attack on Germany's western border. However, the Polish government refused to surrender or negotiate a peace with Germany. Instead, it ordered all units to evacuate Poland and reorganize in France.
Meanwhile, Polish forces tried to move towards the Romanian Bridgehead area, still actively resisting the German invasion. From 17 September to 20 September Polish armies Kraków and Lublin were crippled at the Battle of Tomaszów Lubelski, the second largest battle of the campaign. The city of Lwów capitulated on 22 September because of Soviet intervention; the city had been attacked by the Germans over a week earlier, and in the middle of the siege, the German troops handed operations over to their Soviet allies.. Despite a series of intensifying German attacks, Warsaw—defended by quickly reorganized retreating units, civilian volunteers and militia—held out until 28 September. The Modlin Fortress north of Warsaw capitulated on 29 September after an intense 16-day battle. Some isolated Polish garrisons managed to hold their positions long after being surrounded by German forces. Westerplatte enclave's tiny garrison capitulated on 7 September and the Oksywie garrison held until 19 September; Hel Fortified Area was defended until 2 October. In the last week of September, Hitler made a speech in the city of Danzig in which he said:
Despite a Polish victory at the Battle of Szack, after which the Soviets executed all the officers and NCOs they had captured, the Red Army reached the line of rivers Narew, Western Bug, Vistula and San by 28 September in many cases meeting German units advancing from the other direction. Polish defenders on the Hel peninsula on the shore of the Baltic Sea held out until 2 October. The last operational unit of the Polish Army, General Franciszek Kleeberg's Samodzielna Grupa Operacyjna "Polesie", surrendered after the four-day Battle of Kock near Lublin on 6 October marking the end of the September Campaign.
The Polish September Campaign was an instance of total war. Consequently, civilian casualties were high during and after combat. From the start, the Luftwaffe attacked civilian targets and columns of refugees along the roads to wreak havoc, disrupt communications and target Polish morale. Apart from the victims of the battles, the German forces (both SS and the regular Wehrmacht) are credited with the mass murder of several thousands of Polish POWs and civilians. Also, during Operation Tannenberg, nearly 20,000 Poles were shot at 760 mass execution sites by special units, the Einsatzgruppen, in addition to regular Wehrmacht, SS and Selbstschutz.
Altogether, the civilian losses of Polish population amounted to about 150,000–200,000 while German civilian losses amounted to roughly 3,250 (including 2,000 who died fighting Polish troops as members of a fifth column).
Poland was divided among Nazi Germany, the Soviet Union, Lithuania and Slovakia. On 8 and 13 September 1939, the German military districts of "Posen" (Poznan), commanded by general Alfred von Vollard-Bockelberg, and "Westpreußen" (West Prussia), commanded by general Walter Heitz, were established in conquered Greater Poland and Pomerelia, respectively. Based on laws of 21 May 1935 and 1 June 1938, the German military, Wehrmacht, shared its administrative powers with civilian "chief civil administrators" (Chefs der Zivilverwaltung, CdZ). German dictator Adolf Hitler appointed Arthur Greiser to become the CdZ of the Posen military district, and Danzig's Gauleiter Albert Forster to become the CdZ of the West Prussian military district. On 3 October 1939, the military districts "Lodz" and "Krakau" (Cracow) were set up under command of colonel-generals (generalobersten) Gerd von Rundstedt and Wilhelm List, and Hitler appointed Hans Frank and Arthur Seyß-Inquart as civil heads, respectively. Frank was at the same time appointed "supreme chief administrator" for all occupied territories. On 28 September another secret German-Soviet protocol modified the arrangements of August: all Lithuania was to be a Soviet sphere of influence, not a German one; but the dividing line in Poland was moved in Germany's favour, to the Bug River. On 8 October Nazi Germany formally annexed the western parts of Poland with Greiser and Forster as Reichsstatthalter, while the south-central parts were administered as the so-called General Government led by Frank.
Even though water barriers separated most of the spheres of interest, the Soviet and German troops met on numerous occasions. The most remarkable event of this kind occurred at Brest-Litovsk on 22 September. The German 19th Panzer Corps under the command of Heinz Guderian had occupied the city, which lay within the Soviet sphere of interest. When the Soviet 29th Tank Brigade under the command of S. M. Krivoshein approached, the commanders negotiated that the German troops would withdraw and the Soviet troops would enter the city saluting each other. At Brest-Litovsk, Soviet and German commanders held a joint victory parade before German forces withdrew westward behind a new demarcation line. Just three days earlier, however, the parties had a more hostile encounter near Lwow (Lviv, Lemberg), when the German 137th Gebirgsjägerregimenter (mountain infantry regiment) attacked a reconnaissance detachment of the Soviet 24th Tank Brigade; after a few casualties on both sides, the parties turned to negotiations. The German troops left the area, and the Red Army troops entered Lviv on 22 September. About 65,000 Polish troops were killed in the fighting, with 420,000 others being captured by the Germans and 240,000 more by the Soviets (for a total of 660,000 prisoners). Up to 120,000 Polish troops escaped to neutral Romania (through the Romanian Bridgehead and Hungary), and another 20,000 to Latvia and Lithuania, with the majority eventually making their way to France or Britain. Most of the Polish Navy succeeded in evacuating to Britain as well. German personnel losses were less than their enemies (~16,000 KIA).
Neither side—Germany, the Western Allies or the Soviet Union—expected that the German invasion of Poland would lead to a war that would surpass World War I in its scale and cost. It would be months before Hitler would see the futility of his peace negotiation attempts with Great Britain and France, but the culmination of combined European and Pacific conflicts would result in what was truly a "world war". Thus, what was not seen by most politicians and generals in 1939 is clear from the historical perspective: The Polish September Campaign marked the beginning of the Second World War in Europe, which combined with the Japanese invasion of China in 1937 and the Pacific War in 1941, formed the cataclysm known as World War II.
The invasion of Poland led to Britain and France to declare war on Germany on 3 September. However, they did little to affect the outcome of the September Campaign. This lack of direct help led many Poles to believe that they had been betrayed by their Western allies.
On 23 May 1939, Adolf Hitler explained to his officers that the object of the aggression was not Danzig, but the need to obtain German Lebensraum and details of this concept would be later formulated in the infamous Generalplan Ost. The invasion decimated urban residential areas, civilians soon became indistinguishable from combatants, and the forthcoming German occupation (both on the annexed territories and in the General Government) was one of the most brutal episodes of World War II, resulting in between 5.47 million and 5.67 million Polish deaths (about 20 % of the country's total population, and over 90 % of its Jewish minority) – including the mass murder of 3 million Poles in extermination camps like Auschwitz, in concentration camps, and in numerous ad hoc massacres, where civilians were rounded up, taken to a nearby forest, machine-gunned, and then buried, whether they were dead or not.
According to the Polish Institute of National Remembrance, Soviet occupation between 1939 and 1941 resulted in the death of 150,000 and deportation of 320,000 of Polish citizens, when all who were deemed dangerous to the Soviet regime were subject to sovietization, forced resettlement, imprisonment in labour camps (the Gulags) or murdered, like the Polish officers in the Katyn massacre.[a]
There are several common misconceptions regarding the Polish September Campaign, often resulting from myths perpetrated by Nazi propaganda.
|Invasion of Poland (1939)|
|Part of World War II|
| File:Second World War|
The map shows the beginning of the Second World War in September 1939 in a wider European context.
Soviet Union (After September 17, see details)
| Fedor von Bock|
(Army Group North)
Joined on 17 September:
39 divisions (some of them were never fully mobilized and concentrated),
Total: 950,000[Note 1]
| Germany:[Note 2]|
| Poland:[Note 4]|
The Invasion of Poland in 1939 was a military offensive in which Nazi Germany and later the Soviet Union invaded Poland. It was the start of World War II in Europe. The invasion took place from 1 September to 6 October 1939. The invasion of Poland caused Britain and France to declare war on Germany on 3 September; , they did little to affect the September Campaign. In the end, Poland lost and Germany and the Soviet Union divided the country.