Occupation, Exile and Memory

The fighting in Poland ended at Kock on 6 October 1939, but the war against Poland did not. Within weeks the country had been divided between Germany and the Soviet Union, its western provinces annexed to the Reich, its center turned into a colony called the General Government, and its east absorbed into Soviet republics. Both occupiers set out to destroy the Polish state and the people who might lead it, and the Germans began the persecution of Polish Jews that ended in the Holocaust. Tens of thousands of Polish soldiers, airmen and sailors escaped to fight on from France and Britain, while an underground state formed at home. This chapter covers the cost of September, the two occupations, the exile and the way Poland and the world remember the campaign today.

Why it mattered

Most campaigns end with a surrender and a peace. The Polish campaign of 1939 ended with neither. The Polish government never capitulated; its leaders crossed into Romania on the night of 17–18 September, and a new government was formed in Paris within two weeks. Warsaw, Modlin, Hel and the last field force at Kock laid down their arms under local capitulations, not a national one. Germany and the Soviet Union did not make peace with Poland. They abolished it, drawing a new frontier through the country on 28 September 1939 and governing each half as if the Polish state had never existed.

That is why the story of September does not stop on 6 October. What the occupiers did in the following months grew directly out of the campaign. The German security police units that had followed the army into Poland with lists of names went on killing after the shooting stopped, and the persecution of Polish Jews that began with beatings, forced labor and synagogue burnings in September led within three years to the death camps. In the east, the Soviet NKVD took the Polish officers captured in September to camps from which almost none returned. At the same time the Poles who escaped built an army, an air force and a navy abroad, and their contribution, from the Battle of Britain to the breaking of Enigma, is part of the history of the Western Allies. Americans met the story in Jan Karski’s report to President Roosevelt in 1943, in a congressional investigation of Katyn in 1951–52, and in millions of Polish American families.

The memory of 1939 has also been contested ever since, from the myth of lancers charging tanks to the forty-five years in which Warsaw could not say who had murdered the officers at Katyn. This chapter closes the collection by setting out what the record shows and where to see it today.

The cost of September

No figure for the losses of 1939 is exact, and the main sources disagree by thousands. For the Polish Army the standard estimate, drawn from the Polish official history and repeated by most modern writers, is about 66,000 killed, with some estimates reaching 70,000 or more, and about 133,700 wounded (Polskie Siły Zbrojne w II Wojnie Światowej, vol. 1; Zaloga; Kochanski). Of the dead, somewhere between 3,000 and 7,000 fell fighting the Red Army after 17 September (Topolewski and Polak, as cited by Wikipedia, “Soviet invasion of Poland”). The higher totals include men who died of wounds and soldiers murdered after capture, more than 3,000 of them in German hands in September alone.

The German army announced its losses quickly. In his Reichstag speech of 6 October 1939, Hitler gave the losses of the army, navy and air force up to 30 September as 10,572 killed, 30,322 wounded and 3,404 missing (Hitler, Reichstag speech, 6 October 1939, English text at ibiblio). Later German research, counting men who died of wounds and missing men later found dead, raised the death toll to about 16,000; the figure of 16,343 killed, with about 30,300 wounded and 3,500 missing, is widely cited (Zaloga; Wikipedia, “Invasion of Poland,” infobox). The Wehrmacht also lost several hundred aircraft and tanks: about 246 aircraft and 236 tanks destroyed by one count, with many more damaged and repaired (Wikipedia infobox; Zaloga).

Soviet losses are the most disputed. The figures published by the Russian General Staff historian G. F. Krivosheev in 1997 give 1,475 killed or missing and 2,383 wounded, while Molotov told the Supreme Soviet in October 1939 that 737 had died. Polish historians estimate up to 3,000 Soviet dead and 8,000 to 10,000 wounded (Wikipedia, “Soviet invasion of Poland,” citing Krivosheev and Sanford). The Slovak army, which attacked with the German Fourteenth Army, lost 37 killed (Wikipedia infobox).

Civilian deaths are harder still to count. Estimates for Polish civilians killed during the campaign run from about 100,000 to between 150,000 and 200,000, most of them victims of bombing, shelling and shootings; Warsaw alone lost 15,000 to 25,000 in the siege (Brzoza and Sowa, as cited by Wikipedia). Polish researchers have recorded 714 mass executions by German forces between 1 September and 25 October 1939, with about 16,000 victims (Datner’s research, as summarized in Wikipedia, “German war crimes during the invasion of Poland”). About 1,250 ethnic German civilians in Poland also died, many in Bydgoszcz (Bromberg) in the first days of the war (see Chapter 3).

By the numbers

The dead of the September campaign

Killed and missing, 1 September – 6 October 1939. Where the sources disagree, the label gives the range and the bar and figure show the higher estimate.

Polish civilians (c. 100,000–200,000)200,000

Polish soldiers killed (66,000–70,000)70,000

German killed, later research (c. 16,000–16,343)16,343

German killed (official, 30 Sep 1939)10,572

German missing (3,404–3,500)3,500

Soviet killed or missing (1,475–3,000)3,000

Slovak killed37

The largest single loss was in prisoners. The Germans took about 400,000 to 420,000 Polish soldiers, and the Red Army about 230,000 to 250,000 by Soviet count; the totals usually given for all prisoners run from about 660,000 to 694,000 (Wikipedia, “Invasion of Poland”; Moorhouse). Most of the enlisted men in German hands were eventually released or put to forced labor in the Reich; most of the officers spent the war in prison camps called Oflags. The fate of the officers in Soviet hands is the subject of the Katyn section below. Against those losses stands the number who got away. Up to 120,000 soldiers and airmen crossed into Romania, tens of thousands more into Hungary, and about 20,000 into Lithuania and Latvia (Wikipedia; Kochanski). Tens of thousands slipped out of internment, often with their hosts’ quiet help, and made their way to France.

By the numbers

Wounded, captured and escaped

The other side of the ledger: wounded on each side, Polish soldiers taken prisoner, and those who escaped abroad. The label gives the range; the bar and figure show the higher estimate.

Polish prisoners of Germany (c. 400,000–420,000)420,000

Polish prisoners of the USSR (c. 230,000–250,000)250,000

Polish wounded133,700

Escaped to Romania (up to 120,000)120,000

German wounded (30,300–30,322)30,322

Escaped to Lithuania and Latvia (c. 20,000)20,000

Soviet wounded (2,383–10,000)10,000

The fourth partition: 28 September 1939

The secret protocol of the Molotov–Ribbentrop Pact, signed on 23 August 1939 and described in Chapter 1, had divided Poland roughly along the Narew, Vistula and San rivers, leaving Warsaw on the line and the Lublin region on the Soviet side. When the Red Army invaded on 17 September, told in Chapter 8, Stalin had second thoughts about holding so much ethnically Polish territory, and he wanted Lithuania. Ribbentrop flew to Moscow again, and on 28 September 1939, the day Warsaw capitulated, he and Molotov signed the German–Soviet Boundary and Friendship Treaty.

The treaty and its secret protocols moved the line east to the Pisa, Narew, Western Bug and San rivers. Germany received the Lublin region and the eastern part of the Warsaw province; in exchange Lithuania passed into the Soviet sphere. The two powers agreed to suppress any Polish agitation affecting each other’s territory and to consult on measures to that end (Wikipedia, “German–Soviet Frontier Treaty”; Moorhouse). The new frontier gave the Soviet Union about 200,000 km² of prewar Poland with 13.2 to 13.5 million people, just over half the country; Germany took the rest, about 187,000 km² with roughly 22 million people (Gross; Wikipedia, “Occupation of Poland”). The Wilno (Vilnius) region was handed by the Soviets to Lithuania under a treaty of 10 October 1939, and Slovakia recovered small border districts in the Tatra and Orava regions.

Poles call it the fourth partition, after the three partitions of 1772, 1793 and 1795 by which Russia, Prussia and Austria had wiped Poland off the map. The comparison was not lost on the occupiers. On 31 October 1939 Molotov told the Supreme Soviet that one swift blow by the German army and then the Red Army had been enough to leave nothing of “this ugly offspring of the Versailles Treaty” (Molotov, report to the Supreme Soviet, 31 October 1939). The two armies had already met as partners: at Brest (Brześć) on 22 September, German and Soviet troops held the joint parade described in Chapter 5, and at Lwów and along the Bug the Germans withdrew to the new line in late September and early October.

Hitler came to Warsaw once. On 5 October 1939 he took a victory parade of the German Eighth and Tenth Army troops on Aleje Ujazdowskie, the broad avenue running south from the city center, flew over the ruins and left the same day. Members of the new underground had planted explosives under the route, but they were not set off; the story rests on the conspirators’ postwar accounts. The next day, in the Reichstag speech in which he announced German losses, he offered Britain and France peace on the basis of the new frontier. They refused.

Annexation and the General Government

Germany divided its share in two. The western provinces, including much land that had been Prussian before 1919 but also districts that had never been German, were annexed to the Reich by Hitler’s decree of 8 October 1939 on the administration of the occupied eastern territories, which took effect on 26 October. Two new provinces, called Reichsgaue, were created. Danzig-West Prussia (Danzig-Westpreußen), with its capital at Danzig (Gdańsk), took in the Free City, Polish Pomerania and the Corridor under Gauleiter Albert Forster. The Reichsgau Posen, renamed Wartheland (Warthegau) in January 1940, took in Poznań, Łódź and the lands to the west under Arthur Greiser. Other districts went to existing provinces: the Ciechanów region (Regierungsbezirk Zichenau) and Suwałki to East Prussia, and Polish Upper Silesia, with Katowice, to Silesia (Wikipedia, “General Government” and “Occupation of Poland”; Kochanski).

The annexed territories, about 92,500 km² with about 10.5 million people, were to be made German. Polish was banned from public life, Polish schools closed, Polish names removed from streets and towns; Łódź became Litzmannstadt in 1940 and Gdynia became Gotenhafen. Poles were expelled to make room for ethnic German settlers brought from the Baltic states, Volhynia and elsewhere. The first expulsions began in October 1939, and by the end of 1940 at least 325,000 Poles from the annexed lands had been loaded onto trains and dumped in the General Government, usually with only what they could carry (Wikipedia, “Occupation of Poland,” citing IPN research). Polish property, from farms to factories, was confiscated.

What was left became the General Government, created by Hitler’s decree of 12 October 1939, which came into force on 26 October. Its full name at first was the General Government for the Occupied Polish Territories; the reference to Poland was dropped in 1940. It covered roughly the same area as the annexed lands, about 94,000 km², with about 11.4 million people in December 1939, and was divided into four districts: Kraków, Warsaw, Radom and Lublin. A fifth, Galicia, with Lwów, was added on 1 August 1941 after Germany invaded the Soviet Union (Wikipedia, “General Government”). Warsaw was deliberately passed over as the capital. The seat of government was Kraków, and the governor general lived in the royal castle on the Wawel hill.

The governor general was Hans Frank, born in 1900, the Nazi Party’s leading lawyer, who had been Hitler’s personal attorney and Bavarian minister of justice. He ruled the General Government from 26 October 1939 to the end of the occupation in January 1945. Frank kept a voluminous official diary, later used in evidence against him at Nuremberg, and it records his intentions plainly: the General Government was to be a reservoir of labor for the Reich, its Polish leadership was to be eliminated, and its population was to be kept at the lowest level of education and living standards. Polish universities and secondary schools were closed; only elementary and vocational schools were allowed. Frank was tried by the International Military Tribunal, convicted of war crimes and crimes against humanity, and hanged at Nuremberg on 16 October 1946 (IMT judgment; Kochanski). Forster and Greiser were tried in postwar Poland and executed, Greiser in 1946 and Forster in 1952.

Terror from the first day: the Einsatzgruppen and the Intelligenzaktion

The killing of Poland’s leaders did not begin after the campaign. It was planned before it. In the summer of 1939 Reinhard Heydrich’s Security Police and SD formed special task forces, the Einsatzgruppen, to follow the armies into Poland under the code name Tannenberg. Several thousand strong in all, they carried lists of Poles marked for arrest: activists of the Polish Western Association and the insurgent veterans’ leagues in Silesia and Pomerania, priests, teachers, landowners, officials and politicians. The lists were later compiled into a book, the Sonderfahndungsbuch Polen (Special Prosecution Book–Poland). By the end of 1939 about 47,000 people had been murdered in occupied Poland by the Einsatzgruppen or with their participation, about 7,000 of them Jews (Wikipedia, “German war crimes during the invasion of Poland”; Böhler; Rossino, Hitler Strikes Poland, 2003).

The Wehrmacht was not a bystander. Jochen Böhler’s study of the army in 1939, Auftakt zum Vernichtungskrieg (2006), showed from German war diaries that ordinary army units shot civilians and prisoners in large numbers. A few senior officers protested; Gen. Johannes Blaskowitz, commander in the east after the campaign, sent memoranda in November 1939 and February 1940 complaining of SS atrocities and was moved to another post (Böhler; Kochanski).

From the autumn of 1939 to the spring of 1940, the killings were organized into what German documents called the Intelligenzaktion, the operation against the intelligentsia. The Polish historian Maria Wardzyńska of the Institute of National Remembrance estimated that about 100,000 people were killed in it across the annexed lands and the General Government (Wardzyńska, Był rok 1939, IPN, 2009). It was most savage in Pomerania, where local ethnic Germans organized into an armed militia, the Volksdeutscher Selbstschutz, took part alongside the Security Police and SS units. In the Corridor towns of Tczew, Starogard, Chojnice and many others, Polish teachers, priests, lawyers, merchants and civic leaders were rounded up and shot in nearby forests and gravel pits.

The largest of the Pomeranian killing sites was the forest of Piaśnica, near Wejherowo, about 50 km northwest of Gdańsk. From late October 1939 to the spring of 1940, people were brought there by truck and train and shot at the edge of pits in the woods. The killers were members of Einsatzkommando 16 under Rudolf Tröger, men of the SS Wachsturmbann “Eimann” from Danzig, and local Selbstschutz members. The victims were mainly Polish intellectuals and community leaders from Gdańsk Pomerania and from Gdynia, many with their families, along with Kashubians, Jews, Czechs and German patients from psychiatric hospitals in Pomerania. Estimates of the dead run from 12,000 to 14,000, and some exceed 16,000. In 1944 the Germans made prisoners from the Stutthof camp dig up and burn bodies to destroy the evidence (Wikipedia, “Piaśnica massacres,” citing Grot and Wardzyńska). Kurt Eimann was tried in Hamburg in 1968, but only for the murder of the German patients, and sentenced to four years.

In the General Government the policy continued in 1940 under the name Außerordentliche Befriedungsaktion, the Extraordinary Pacification Action or AB-Aktion, which Frank discussed with his officials in May 1940. Its best-known killing ground is Palmiry, a clearing in the Kampinos Forest about 30 km northwest of Warsaw, close to the ground where the Polish units fought their way out of the Bzura pocket in September (see Chapter 6). From December 1939 to July 1941, prisoners from Warsaw’s Pawiak prison and other jails were driven there and shot, more than 1,700 of them in all, Poles and Jews (Wikipedia, “Palmiry massacre”). On 20–21 June 1940 the victims included Maciej Rataj, former marshal of the Sejm; Mieczysław Niedziałkowski, the Socialist leader; and Janusz Kusociński, who had won the 10,000 meters at the 1932 Olympic Games in Los Angeles. Kusociński had fought in the defense of Warsaw in September and been wounded twice.

The Palmiry graves were found because of the courage of a forester, Adam Herbański, and his men of the Polish Forest Service, who secretly marked them during the occupation. After the war the Polish Red Cross exhumed 24 mass graves and more than 1,700 bodies, and in 1948 the clearing became a national cemetery, today holding about 2,200 burials including victims brought from other execution sites around Warsaw. A museum was added in 1973 (Wikipedia, “Palmiry massacre”).

Sonderaktion Krakau: the professors’ arrest, 6 November 1939

The most notorious single blow against Polish learning fell in Kraków, the new German capital. The Jagiellonian University, founded in 1364, had tried to open its academic year in early November 1939 as usual. SS-Obersturmbannführer Bruno Müller, commander of the Security Police in Kraków, invited the professors to a lecture on German attitudes toward science and learning, to be held at noon on 6 November in lecture room 66 of the Collegium Novum. There was no lecture. Müller told the assembled academics that the university had opened without permission and that Poles had always been hostile to German science, and then had everyone in the room arrested (Wikipedia, “Sonderaktion Krakau”).

The number seized is usually given as 183 or 184: 105 professors and 33 lecturers of the Jagiellonian University, 34 professors and doctors of the Academy of Mining, and a few others, including visiting scholars from Lublin and Wilno, plus a dozen or more employees and students. After a few weeks in prisons in Kraków and Breslau (Wrocław), they were sent on 27 November 1939 to the Sachsenhausen concentration camp near Berlin. Protests followed from abroad, including from the Vatican and from Mussolini’s Italy, and on 8 February 1940 the Germans released 101 professors over the age of 40. Others were freed later, some only in January 1941 after transfer to Dachau. By then the ordeal had killed at least seventeen of them, twelve in the camp within three months, among them the literary historian Ignacy Chrzanowski, the legal historian Stanisław Estreicher and the zoologist Michał Siedlecki (Wikipedia, “Sonderaktion Krakau”).

The professors who came home began teaching again, illegally, in the underground universities that operated in Kraków and Warsaw throughout the occupation. One student of the Jagiellonian University’s clandestine theology courses, from 1942, was a young quarry worker training for the priesthood in secret: Karol Wojtyła, later Pope John Paul II.

The persecution of Polish Jews begins

Poland in 1939 had the largest Jewish community in Europe, about 3.3 million people, a tenth of the population. Roughly two million lived in the German zone after 28 September; perhaps 300,000 fled east in the autumn of 1939 to the Soviet zone, where about 1.3 million more already lived (Kochanski; USHMM). For the Jews of German-occupied Poland, the persecution began with the invasion itself. German soldiers and police beat, robbed and humiliated Jews in the streets, cut off the beards of religious men for the cameras, and burned synagogues; in some towns they killed hundreds. In Przemyśl, on the San, several hundred Jewish men were shot in mid-September 1939, before the town was handed over to the Soviets (Rossino; Böhler).

Legal persecution followed within weeks. Heydrich’s instruction of 21 September 1939 ordered the Einsatzgruppen to concentrate Jews in larger towns near railway lines. In the General Government, Frank’s decrees of 26 October imposed forced labor on Jews, and from 1 December 1939 all Jews over the age of ten had to wear a white armband with a blue Star of David. Jewish businesses were marked and seized, Jewish bank accounts frozen, and Jewish councils (Judenräte) appointed to carry out German orders. In the annexed territories, Jews were expelled into the General Government along with Poles.

The first ghetto came early. At Piotrków Trybunalski, the town where the German Tenth Army’s panzers broke through on 5–6 September (see Chapter 3), the local German commander ordered on 8 October 1939 that the Jews be confined to a district of the old town. It is generally regarded as the first ghetto in occupied Europe. Up to 28,000 people were eventually packed into an area where about 6,000 had lived before (Wikipedia, “Piotrków Trybunalski Ghetto,” citing USHMM and Yad Vashem). The great ghettos followed: Łódź (Litzmannstadt) was sealed at the end of April 1940, and Warsaw in November 1940, with more than 400,000 people behind its walls at its height (USHMM, “Warsaw”; “Lodz”). In October 1942 about 22,000 Jews of Piotrków were deported to Treblinka and Majdanek. About three million Polish Jews, some 90 percent of the prewar community, were murdered in the Holocaust.

The Soviet occupation and the deportations of 1940–41

In the east the method was different but the aim was the same: to destroy the Polish state and its leadership and to make the territory Soviet. After staged elections to “people’s assemblies” in late October 1939, with one approved candidate for each seat, the assemblies asked to join the Soviet Union, and on 1 and 2 November 1939 the Supreme Soviet incorporated the territories into the Ukrainian and Belorussian Soviet republics. All residents were declared Soviet citizens, liable to Soviet conscription and Soviet law. Polish currency was withdrawn, land, businesses and bank deposits were taken, and the NKVD began arresting officials, police, judges, landowners, political activists, priests and anyone else classed as an “enemy of the people” (Gross, Revolution from Abroad; Kochanski). The Institute of National Remembrance estimates that about 150,000 Polish citizens died as a result of Soviet actions in 1939–41 (Wikipedia, “Occupation of Poland”).

The best remembered of the Soviet measures were the mass deportations. Four great operations, each carried out in a single night or a few days by NKVD squads with lists, took whole families from their homes, loaded them into freight cars and sent them east to labor settlements, collective farms and camps in northern Russia, Siberia and Kazakhstan:

• 10 February 1940: about 140,000 people, mostly military settlers (veterans of 1920 given land in the east), foresters, civil servants and their families, in temperatures well below freezing (Museum of Siberian Memory, Białystok).
• 13 April 1940: about 61,000, chiefly the families of men already arrested, including the wives and children of the officers and policemen then being shot at Katyn and the other sites, most of them sent to Kazakhstan.
• Late June 1940: about 78,000, mostly refugees from the German zone who had refused Soviet citizenship or registered to return home; a large share were Jews.
• May–June 1941: a last wave of several tens of thousands, cut short by the German invasion of the Soviet Union on 22 June.

NKVD documents opened after 1990 count about 320,000 to 330,000 people deported in these operations. Wartime Polish estimates, which included prisoners, men conscripted into the Red Army and labor battalions, and others taken east, ran to a million or more, and historians still debate the gap (Museum of Siberian Memory; Kochanski). Thousands died on the journey and in the first winters. Survival came by an accident of politics. After Germany attacked the Soviet Union, Sikorski and the Soviet ambassador in London, Ivan Maisky, signed an agreement on 30 July 1941, and in August the Soviet Union granted an “amnesty” to Polish citizens it had never had the right to imprison. A Polish army formed in the Soviet Union under Gen. Władysław Anders, and in 1942 about 115,000 soldiers and civilians were evacuated with it to Iran. Its soldiers later fought at Monte Cassino.

Katyn, April–May 1940

Of the Polish soldiers captured by the Red Army in September 1939, most of the enlisted men were released or handed over to the Germans within weeks. The officers, and the police, border guards and prison officers, were not. About 15,000 of them were held in three special NKVD camps: officers at Kozielsk and Starobielsk, police and others at Ostashkov. Many were reservists called up in August 1939, which meant that the camps held a cross-section of the Polish professional class: doctors, lawyers, engineers, teachers, scientists, writers and civil servants, along with career officers, among them generals and an admiral (Kochanski; Cienciala, Lebedeva and Materski, Katyn: A Crime Without Punishment, 2007).

On 5 March 1940 the Soviet Politburo approved a proposal by the NKVD chief, Lavrentiy Beria, to shoot the prisoners in the three camps and Polish prisoners held in NKVD jails in western Belarus and Ukraine as “hardened and uncompromising enemies of Soviet authority.” Stalin’s signature heads the document. The killings were carried out from early April to May 1940. Prisoners from Kozielsk, 4,421 by the NKVD’s own count, were taken to the Katyn Forest near Smolensk and shot there; 3,820 from Starobielsk were shot in the NKVD prison at Kharkiv and buried at Piatykhatky; 6,311 from Ostashkov were shot in the NKVD prison at Kalinin (Tver) and buried at Mednoye. A further 7,305 prisoners from the jails were shot at other places, probably including Bykivnia near Kyiv and Kurapaty near Minsk. A Soviet document of 1959 gives the total as 21,857 (Wikipedia, “Katyn massacre,” citing the documents released by Russia in 1992). The name of one site, Katyn, has come to stand for all of them.

The families learned nothing. Letters stopped in the spring of 1940. When the Anders army formed in 1941–42, its officers searched the Soviet Union for thousands of missing comrades and were told they had escaped to Manchuria. On 13 April 1943 Berlin radio announced that German troops had found mass graves of Polish officers in the Katyn Forest. Goebbels saw a chance to split the Allies; the Polish government asked the International Red Cross to investigate, and Stalin used the request as a pretext to break off relations with it on 25 April 1943. A Soviet commission under Nikolai Burdenko declared in January 1944 that the Germans had done it, and the Soviet prosecutors put the charge into the indictment at Nuremberg. After hearing witnesses in July 1946, the tribunal left Katyn out of its judgment (Wikipedia; Cienciala et al.).

Katyn has an American chapter. In May 1943 the Germans took a group of Allied prisoners of war to see the graves, among them two American officers, Lt. Col. John H. Van Vliet Jr. and Capt. Donald B. Stewart. Both concluded from the condition of the bodies and the evidence around them that the Soviets were responsible. Van Vliet reported to Army intelligence in 1945, and his report vanished; he wrote it again in 1950 (Moscow Times, 10 September 2012). In Washington, where the Soviet alliance came first, the government said nothing. In 1951, after pressure from Polish American organizations, the House of Representatives created a select committee chaired by Rep. Ray J. Madden of Indiana. The Madden Committee held hearings from October 1951 to November 1952 in Washington, Chicago, London, Frankfurt, Berlin and Naples, the first congressional committee to take testimony abroad; it heard 81 witnesses and took more than 100 depositions (East Carolina University, Congress Investigates). Its final report of 22 December 1952 found unanimously that the NKVD had committed the massacre, recommended that the case be taken to the International Court of Justice, and criticized American officials who had ignored or suppressed evidence (Wikipedia, “Madden Committee”). On 10 September 2012 the U.S. National Archives released about 1,000 pages of declassified documents on what the government had known (Moscow Times).

Moscow kept its version for almost fifty years. In communist Poland, Katyn could not be discussed honestly; the official line blamed the Germans, and unofficial memorials giving the date of death as 1940 were taken down by the authorities. On 13 April 1990, the 47th anniversary of the German announcement, the Soviet news agency TASS published a statement expressing “profound regret” and admitting NKVD responsibility. In October 1992 Russian President Boris Yeltsin gave Poland copies of the 1940 documents, including the Politburo decision. Polish war cemeteries were opened at Kharkiv, Katyn and Mednoye in 2000. On 10 April 2010 the plane carrying President Lech Kaczyński and 95 others to the 70th-anniversary commemoration at Katyn crashed near Smolensk, killing everyone on board.

The government in exile

The Polish state never stopped existing in law. President Ignacy Mościcki, interned in Romania after crossing the border on 17–18 September (see Chapter 8), used his constitutional power to name a successor and resigned. On 30 September 1939, at the Polish embassy in Paris, Władysław Raczkiewicz took the oath as president, and he appointed Gen. Władysław Sikorski prime minister. Sikorski, born in 1881, had commanded an army against the Bolsheviks in 1920 and served as prime minister in 1922–23, but had been out of favor with the Piłsudski camp and without a command in September 1939. On 7 November 1939 he also became commander in chief in place of Marshal Edward Rydz-Śmigły, who was interned in Romania (Wikipedia, “Polish government-in-exile”; Kochanski).

The new government was recognized at once by France, Britain and the United States. It sat first in Paris and then, from late 1939, at Angers in the Loire valley, where President Raczkiewicz lived at the Château de Pignerolle from 2 December. When France fell in June 1940 it moved to London, where it remained for the rest of the war. Sikorski was killed when his plane crashed on takeoff at Gibraltar on 4 July 1943. Britain and the United States withdrew recognition on 5 July 1945, after the Yalta settlement, in favor of the Soviet-backed government in Warsaw; the exile presidency continued in London until 22 December 1990, when its last holder, Ryszard Kaczorowski, handed the presidential insignia to Lech Wałęsa, the first freely elected president of postwar Poland, at the Royal Castle in Warsaw (Wikipedia).

Fighting on: France, Norway and the evacuation of 1940

Sikorski’s first task was to build an army in France, and the men came. Soldiers interned in Romania and Hungary escaped from camps that were often loosely guarded, traveled by train, by ship from Black Sea and Adriatic ports, or on foot across the Balkans, and reported to Polish recruiting centers in France. They were joined by volunteers from the large Polish immigrant community there, much of it miners in the north. By 15 June 1940 the Polish Army in France numbered 84,461 men (Wikipedia, “Polish Army in France,” citing Polish sources). Its main formations were the 1st Grenadier Division, the 2nd Rifle Division, the 10th Armored Cavalry Brigade under Gen. Stanisław Maczek, who had led the 10th Motorized Cavalry Brigade in September, and the Independent Podhale Rifle Brigade, a mountain formation of about 5,000 men.

The Podhale Brigade was the first into action. Raised for the Allied expedition to help Finland, it went instead to Norway and fought around Narvik from 28 May to early June 1940, alongside French, British and Norwegian troops, in the battle that retook the port before the Allies withdrew. When the German offensive in France opened on 10 May, the Polish divisions were still forming and short of equipment. The 1st Grenadier Division fought in Lorraine before disbanding on 21 June; the 2nd Rifle Division, after fighting near Belfort, crossed into Switzerland on 20–21 June and was interned there, about 13,000 men in all, for the rest of the war. Maczek’s brigade fought in Champagne and Burgundy until it ran out of fuel (Wikipedia, “Polish Army in France”).

When France asked for an armistice, Sikorski flew to London and on 19 June met Winston Churchill, who agreed to bring the Polish forces to Britain. British and Polish ships evacuated Polish troops from Atlantic ports in the following days, the last from Saint-Jean-de-Luz near the Spanish border. Estimates of how many reached Britain range from about 20,000 to 35,000, including most of the air force personnel (Wikipedia, “Polish Army in France”; Kochanski). An Anglo-Polish military agreement of 5 August 1940 put the Polish forces in Britain on a formal footing as the armed forces of a sovereign ally. In Scotland the army rebuilt itself around the I Polish Corps, and Maczek’s survivors became the core of the 1st Armored Division that fought in Normandy in 1944. Their story continues in the Allied campaigns of 1944–45, at Falaise, Arnhem, Monte Cassino and Bologna.

In the air: the Polish Air Force and No. 303 Squadron

The Polish Air Force had, contrary to legend, survived September as an organization. Its combat squadrons had fought to the end of their fuel and spare parts, as told in Chapter 4, and on 17–18 September most of the remaining aircraft and thousands of airmen and cadets crossed into Romania. Many airmen reached France and flew there in May–June 1940, but the French had found it hard to use them, and Polish units in France flew mostly obsolete or unfamiliar aircraft. In Britain it was different. The RAF was short of trained fighter pilots, and the Poles, many of them with years of flying experience and combat in 1939, were the largest foreign contingent in Fighter Command in the Battle of Britain: 145 Polish fighter pilots took part (Wikipedia, “Polish Air Forces in France and Great Britain”; Cynk).

After courses in English, RAF procedures and the Hurricane, the RAF formed two Polish fighter squadrons in July and August 1940, No. 302 (City of Poznań) and No. 303. No. 303 moved to RAF Northolt, west of London, on 2 August. Its British commander, Squadron Leader Ronald Kellett, served alongside a Polish commander, Major Zdzisław Krasnodębski, who had led the III/1 Fighter Wing of the Pursuit Brigade over Warsaw in 1939. On 30 August, during a training flight, Flying Officer Ludwik Paszkiewicz broke away to attack a formation of German bombers and shot down a Messerschmitt Bf 110. The squadron was declared operational the next day (Wikipedia, “No. 303 Polish Fighter Squadron”).

In the six weeks that followed, during the heaviest fighting of the Battle of Britain, No. 303 claimed 126 German aircraft destroyed, the highest total of any squadron in Fighter Command in the battle. Postwar research using German loss records has reduced the figure, as it has for every squadron: the Polish historian Jacek Kutzner’s count is 58.8 aircraft, and other estimates are about 55 to 60 (Wikipedia, citing Kutzner). The cost was 18 Hurricanes lost and seven pilots killed. Two names stand out. The squadron’s top scorer, with 17 confirmed victories between 2 and 30 September, was Sgt. Josef František, a Czech who had escaped to Poland in June 1939, flown unarmed reconnaissance aircraft for the Poles in September and chosen to stay with them; he was the highest-scoring non-British Allied pilot of the battle, and he was killed in a crash at Ewell, Surrey, on 8 October 1940, probably from exhaustion (Wikipedia, “Josef František”). The second was the squadron’s commander from 7 September, Witold Urbanowicz, described below.

At sea: the Orzeł and the Błyskawica

The navy’s war in exile began before the invasion. Under the Peking Plan, the destroyers Błyskawica, Burza and Grom left Gdynia on 30 August 1939 and reached Britain on 1 September, and two submarines, Wilk and Orzeł, escaped from the Baltic during the campaign. The Orzeł’s escape is told in Chapter 7: interned at Tallinn after putting in there on 14 September, her crew broke out on the night of 17–18 September, without charts and with most of her torpedoes removed, and reached Rosyth in Scotland on 14 October 1939 (Peszke, The Polish Navy 1918–1945).

Under British operational command the Polish ships fought from the first months. On 8 April 1940 the Orzeł torpedoed and sank the German transport Rio de Janeiro off Lillesand in southern Norway, carrying troops for the invasion of Norway that began the next day; Norwegian rescuers who picked up German soldiers in uniform gave one of the first warnings of the invasion, though it was not acted on in time. On 23 May 1940 the Orzeł sailed from Rosyth on patrol in the North Sea and never returned; she was declared lost in June 1940, probably to a mine, with all hands. The Grom was sunk by German aircraft off Narvik on 4 May 1940. The Błyskawica served throughout the war, from Narvik and Dunkirk to the Atlantic convoys and the invasion of Normandy, and in May 1942, while refitting at Cowes on the Isle of Wight, her anti-aircraft guns helped defend the town during a heavy German air raid (Peszke). She returned to Poland after the war and is now a museum ship at Gdynia.

The Enigma legacy

Poland’s most valuable contribution to the Allied war had been made before the first shot. As told in Chapter 1, Marian Rejewski, Jerzy Różycki and Henryk Zygalski of the Polish Cipher Bureau had broken the German army’s Enigma in 1932–33, and at Pyry, south of Warsaw, on 25–26 July 1939 they gave the British and French their methods and a replica machine each. Gordon Welchman, one of the leaders of Hut 6 at Bletchley Park, later wrote that without the Polish start the British might have broken the army and air force keys much later (Welchman, The Hut Six Story, 1982; Kozaczuk, Enigma, 1984).

The Poles themselves never worked at Bletchley. On 5 September 1939 the Cipher Bureau left Warsaw by special train; on 17 September its staff crossed into Romania, and the three mathematicians went to the French embassy in Bucharest, which sent them to France. From 20 October 1939 they worked at PC Bruno, the French radio-intelligence center in the Château de Vignolles at Gretz-Armainvilliers east of Paris, in a joint unit with the French and with Spanish Republican cryptographers. With Zygalski sheets prepared at Bletchley and sent to them, they solved their first wartime Enigma key, for 28 October 1939, on 17 January 1940, and the two centers exchanged results by teletype. After the fall of France, Capt. Gustave Bertrand flew the team to Algeria on 24 June 1940, and in October it resumed work in secret in unoccupied France at a station code-named Cadix, the Château des Fouzes near Uzès (Wikipedia, “Marian Rejewski”; Kozaczuk).

Różycki did not survive. On 9 January 1942 he was among several Polish cryptologists lost when the French passenger ship Lamoricière, carrying them back from a posting in Algeria, sank in a storm off the Balearic Islands. When the Germans occupied the rest of France in November 1942, Cadix was evacuated. Rejewski and Zygalski crossed the Pyrenees on 29 January 1943, were arrested in Spain and held in prisons for more than three months, and after their release on 4 May went by way of Portugal and Gibraltar to Britain, arriving on 3 August 1943. They were not brought into Bletchley’s work on Enigma. The Polish Army posted them to its signals unit at Stanmore Park, where they worked on German SS and SD hand ciphers until the end of the war (Wikipedia, “Marian Rejewski”).

Rejewski returned to Poland in November 1946 and lived quietly as an accountant, investigated repeatedly by the security police, until the story of the Polish breaking of Enigma came out in the 1970s. It had been kept secret during the war and after, and when the British began publishing accounts of Ultra in 1974, they at first said little about the Poles. Rejewski gave his own accounts to Polish historians and to Kozaczuk, and lived to see them published. He died in Warsaw on 13 February 1980 and is buried in the Powązki Military Cemetery. Poland awarded him and Zygalski the Grand Cross of the Order of Polonia Restituta posthumously in 2000, and in 2014 the Institute of Electrical and Electronics Engineers named “the first breaking of Enigma ciphers by the Polish Cipher Bureau, in 1932–1939” an IEEE Milestone (Wikipedia, “Marian Rejewski”). Zygalski stayed in Britain, taught mathematics and died there in 1978.

The Underground: Service for Poland’s Victory

Resistance at home began before the campaign ended. On the night of 26–27 September 1939, as Warsaw negotiated its capitulation, Gen. Michał Tokarzewski-Karaszewicz, with the authority of the city’s commander, Gen. Juliusz Rómmel, founded a secret military organization called Służba Zwycięstwu Polski (Service for Poland’s Victory, SZP). Its officers went into hiding instead of into the prison camps, kept their weapons where they could, and began to recruit. On 13 November 1939 Sikorski’s government reorganized it as the Związek Walki Zbrojnej (Union of Armed Struggle, ZWZ), under the command of the government in exile, and on 14 February 1942 it became the Armia Krajowa, the Home Army, which at its height numbered more than 400,000 sworn members (Wikipedia, “Polish Underground State”; Kochanski).

Around the army grew a whole clandestine state. From December 1940 a Government Delegate for Poland represented the London government, with departments that mirrored the ministries, underground courts, a press of hundreds of titles, the secret schools and universities, and, from December 1942, the Council to Aid Jews, Żegota. The September campaign also left fighters in the field who never surrendered. The best known was Maj. Henryk Dobrzański, “Hubal,” whose detachment of cavalry fought on in the Kielce region until he was killed on 30 April 1940 (see Chapter 8). Linking the underground to London required couriers who crossed occupied Europe on foot and by train, and the most famous of them was a young officer who had fought in September.

Timeline

Occupation and exile, 1939–1943

1. 27 Sep 1939Service for Poland’s Victory (SZP) founded in Warsaw.
2. 28 Sep 1939German–Soviet Boundary and Friendship Treaty signed in Moscow.
3. 30 Sep 1939Raczkiewicz sworn in as president in Paris; Sikorski named prime minister.
4. 8 Oct 1939Annexation decree; the Piotrków Trybunalski ghetto ordered.
5. 26 Oct 1939Annexation and the General Government come into force; Hans Frank governor general.
6. 1–2 Nov 1939Supreme Soviet incorporates eastern Poland.
7. 6 Nov 1939Sonderaktion Krakau: 183–184 academics arrested.
8. 13 Nov 1939SZP reorganized as the Union of Armed Struggle (ZWZ).
9. Dec 1939Executions at Palmiry begin.
10. 10 Feb 1940First Soviet mass deportation.
11. 5 Mar 1940Politburo approves the shooting of Polish prisoners.
12. Apr–May 1940Katyn, Kharkiv and Kalinin massacres.
13. 19–25 Jun 1940Polish forces evacuated from France to Britain.
14. 20–21 Jun 1940Rataj, Niedziałkowski and Kusociński shot at Palmiry.
15. 31 Aug 1940No. 303 Squadron declared operational.
16. 14 Feb 1942The ZWZ becomes the Home Army (AK).
17. 13 Apr 1943Germany announces the Katyn graves.
18. 4 Jul 1943Sikorski killed at Gibraltar.
19. 28 Jul 1943Jan Karski reports to Roosevelt at the White House.

Jan Karski: from the San to the White House

Jan Karski’s story links the September campaign, the underground, the Holocaust and the United States more directly than any other. A reserve artillery officer captured by the Red Army in 1939, he escaped, joined the underground and became its best-known courier; his career is told in the card below.

Karski’s report reached the Allied leaders at a moment when they already had evidence of the extermination of the Jews, and the joint Allied declaration of 17 December 1942 had condemned it. What he could add was an eyewitness. In Washington he met, besides the President, members of the cabinet, Supreme Court Justice Felix Frankfurter, Jewish leaders and journalists. Frankfurter told him that he could not believe what he had been told, which Karski later understood not as an accusation of lying but as a refusal to absorb it. The meeting with Roosevelt took place in the White House on 28 July 1943, arranged by the Polish ambassador, Jan Ciechanowski. The Polish record of the conversation shows that the President asked mostly about conditions in Poland, the underground, the Germans’ methods and the Soviet question, and also about the fate of the Jews (Polish History Museum, record of the Karski–Roosevelt conversation).

In their words

Is the material situation in Poland really that bad?

Presidential Medal of Freedom · 2012

Jan Karski, honored by the United States

President Barack Obama announced on 23 April 2012 that Jan Karski would receive the Presidential Medal of Freedom, the highest civilian honor of the United States, and presented it posthumously on 29 May 2012; it was accepted by Adam Daniel Rotfeld, a former Polish foreign minister. In his remarks the President referred to “a Polish death camp” instead of a German death camp in occupied Poland; after protests from Warsaw he called it a misstatement, and Polish President Bronisław Komorowski accepted the explanation (Wikipedia, “Jan Karski”). A bronze statue of Karski seated on a bench stands on the Georgetown University campus where he taught.

The myths of September

The Polish campaign was the first battle of the Second World War in Europe, fought before most of the world’s journalists arrived and reported to the West largely through German communiqués and newsreels. Several images from that reporting became fixed in popular memory and are still repeated in books, documentaries and classrooms. Three matter most.

The comparison with France is not meant to diminish the French; the circumstances differed in every way. Poland’s long frontiers were outflanked from the start by German territory in East Prussia, Pomerania, Silesia and Slovakia, and the Soviet invasion of 17 September struck the region where the Polish command had planned its last stand. Nor was the German army of 1939 the machine of legend. It was still mostly infantry on foot with horse-drawn supply, and historians such as Karl-Heinz Frieser have shown that “blitzkrieg” was a journalists’ word, not a German doctrine.

Remembering September: 1 September, 17 September, 13 April

Poland marks three dates for the events in this collection. On 1 September the anniversary of the invasion is commemorated at Westerplatte at 04:45, the hour the Schleswig-Holstein opened fire, and at Wieluń at dawn, by Polish accounts the hour of the first bombs; presidents and foreign leaders have attended both. In 2009, for the 70th anniversary, the German chancellor Angela Merkel and the Russian prime minister Vladimir Putin came to Westerplatte. In 2019, for the 80th, Germany’s president Frank-Walter Steinmeier spoke at Wieluń and asked forgiveness, and American Vice President Mike Pence attended the national ceremony in Warsaw in place of President Donald Trump.

On 17 September Poland remembers the Soviet invasion, and the day is also observed as Sybiraks’ Day, for the people deported to Siberia and Kazakhstan. On 13 April, the anniversary of the German announcement of 1943, Poland observes the Day of Remembrance of the Victims of the Katyn Massacre, established by the Sejm in 2007 (dzieje.pl). For the communist government, the dates were difficult in different ways. The German invasion could be commemorated freely, and the Monument to the Defenders of the Coast at Westerplatte was unveiled in 1966. The Soviet invasion and Katyn could not. Unofficial Katyn memorials appeared in Warsaw’s Powązki cemetery and were removed, and the subject became a test of political honesty for the opposition in the 1980s.

The Polish American community kept the memory alive in the United States when it could not be spoken in Poland. Its organizations pressed for the Madden Committee in 1951, and in June 1991 the Katyń Memorial by the Polish American sculptor Andrzej Pityński was unveiled at Exchange Place in Jersey City, New Jersey, facing the Hudson. It is about 10 m (34 feet) high and shows a soldier bound and gagged, impaled on a bayonet. When the city planned to move it in 2018, protests from Polish Americans and the Polish government followed, and on 20 December 2018 the Jersey City Council voted unanimously that the monument would stay where it stands in perpetuity (Wikipedia, “Katyń Memorial (Jersey City)”). Baltimore and other American cities have Katyn memorials of their own.

Memorials and museums today

The places of September are well marked in Poland, and most are easy to visit. The two most important are in Gdańsk, within a few kilometers of each other. Westerplatte, where the garrison of the Military Transit Depot held out from 1 to 7 September (see Chapter 2), is a peninsula at the mouth of the harbor channel with the ruins of the barracks, the restored Guardhouse No. 1, the graves of the defenders and the monument on its mound. In the old city, the building of Polish Post Office No. 1 on what is now Defenders of the Polish Post Office Square houses a museum of its defense on 1 September and of the trial and execution of its defenders on 5 October 1939.

Beside the post office stands the Museum of the Second World War, whose leaning tower of glass and red concrete rises above the Radunia canal. Founded in 2008 and opened to the public on 23 March 2017, it has one of the largest permanent exhibitions on the war in Europe, mostly underground, from the road to war through occupation, the Holocaust and the postwar settlement, with exhibits ranging from a Ju 87 Stuka to an Enigma machine (Wikipedia, “Museum of the Second World War”). Its exhibition has been the subject of political controversy in Poland since before it opened, and the museum also administers the site at Westerplatte, where a new museum has been planned.

Elsewhere, smaller memorials mark the battlefields of earlier chapters, from the bunkers of Wizna and Węgierska Górka to Mokra, Kutno, Modlin and Hel. In Poznań, where the Enigma mathematicians studied, the Enigma Cipher Center tells their story, and Bletchley Park has a memorial to the Polish codebreakers.

How to visit

Gdańsk is the natural starting point and has direct flights from several European hubs. Allow a full day for the Museum of the Second World War and an hour or two for the Polish Post Office museum next door. Westerplatte is about 7 km north of the old city; city buses run there, and in summer tourist boats sail from the old town quay down the harbor channel, past the place where the Schleswig-Holstein lay moored, which is the best way to understand the ground. The Piaśnica forest is about 50 km northwest, near Wejherowo, reachable by commuter train and taxi; the Błyskawica is moored at Gdynia, 25 km north of Gdańsk, and the Hel peninsula is a day trip beyond.

Warsaw has the Katyn Museum in the Citadel, the Polish Army Museum, the Pawiak prison museum and the Warsaw Rising Museum, which covers the later war. Palmiry is about 30 km northwest of the city on the edge of the Kampinos National Park, where marked trails also cross the ground of the Bzura breakout. Wieluń is about 100 km southwest of Łódź, and Mokra a short drive from it. Wizna is in the northeast near Łomża, best reached by car. The Katyn and Mednoye cemeteries are in Russia and the Kharkiv cemetery in Ukraine; the U.S. State Department has advised Americans not to travel to Russia or Ukraine since 2022, so for now those sites are best visited through the Katyn Museum in Warsaw.

Questions readers ask

Did Poland ever surrender in 1939?

No. Individual commands capitulated, Warsaw on 28 September, Modlin on 29 September, Hel on 2 October and the Polesie group at Kock on 6 October, but the Polish government never signed a surrender. It reconstituted itself in Paris on 30 September and fought on with the Allies until 1945.

How many people died at Katyn?

Soviet documents give 21,857 Polish prisoners shot in April and May 1940, of whom about 4,400 were killed in the Katyn Forest itself; the others were shot at Kharkiv, Kalinin (Tver) and other places. The figure usually quoted is about 22,000.

Did the United States know about Katyn during the war?

It had strong indications. Two American prisoners of war, Lt. Col. John Van Vliet and Capt. Donald Stewart, were taken to the graves in May 1943 and concluded the Soviets were guilty, and other reports reached Washington. The Madden Committee concluded in 1952 that officials had failed to act on the evidence, and documents released in 2012 showed that some of it had been kept secret.

How it connects

This chapter closes the collection. Its threads begin in Chapter 1, with the secret protocol that planned the partition and the Enigma breakers whose work reached Bletchley; run through the first shots at Westerplatte and the Polish Post Office, the frontier battles, the air war and the Kościuszko Squadron, Wizna and Brest, the Bzura and the siege of Warsaw and the coast and the Orzeł; and lead to 17 September and the last battles, where the prisoners who died at Katyn were taken and the government crossed into Romania.

Beyond Poland, the story connects to the site’s other Second World War collections. Poland’s war began two years after the clash at the Marco Polo Bridge began China’s, and two years and three months before Pearl Harbor brought the United States in; the Polish destroyers that escaped in 1939 went on to escort convoys in the Battle of the Atlantic. For short answers about the whole campaign, see the collection’s questions and answers.

What happened afterward

The partition of 1939 lasted until 22 June 1941, when Germany invaded the Soviet Union and all of prewar Poland came under German rule. The General Government became the center of the Holocaust, with the death camps of Bełżec, Sobibór, Treblinka and Majdanek, while Auschwitz and Chełmno lay in the annexed lands. The Home Army fought the Warsaw Uprising of 1944, and the Polish forces in the West fought in Italy, Normandy and the Low Countries. At Tehran and Yalta the Allied leaders agreed that Poland’s eastern frontier would follow roughly the line of 1939, with compensation in German territory in the west. Poland lost 5.6 to 5.8 million citizens in the war by the IPN’s estimate, roughly half of them Polish Jews (Wikipedia, “Occupation of Poland,” citing IPN).

Many of the soldiers, airmen and sailors who had escaped in 1939 never went home. They had fought for a free Poland and would not return to one ruled by communists, and those who did, like Urbanowicz, were often persecuted. The Polish forces were left out of the London Victory Parade of June 1946 to avoid offending the Soviet Union and the new Warsaw government; sources disagree on whether No. 303’s airmen were invited and refused or were not invited at all, but the episode is still remembered with bitterness (Wikipedia, “No. 303 Polish Fighter Squadron”). Tens of thousands settled in Britain under the Polish Resettlement Act of 1947, and many others in the United States, Canada and Australia, joining the older Polish emigration. Poland regained full independence in 1989, and in 1990 the last president in exile handed his insignia to an elected president in Warsaw, closing the account opened on 30 September 1939.

Sources

• Steven J. Zaloga, Poland 1939: The Birth of Blitzkrieg (Osprey, 2002).
• Roger Moorhouse, First to Fight: The Polish War 1939 (Bodley Head, 2019; U.S. edition Poland 1939: The Outbreak of World War II, Basic Books, 2020).
• Halik Kochanski, The Eagle Unbowed: Poland and the Poles in the Second World War (Allen Lane / Harvard University Press, 2012).
• Jochen Böhler, Auftakt zum Vernichtungskrieg: Die Wehrmacht in Polen 1939 (Fischer, 2006); Alexander B. Rossino, Hitler Strikes Poland: Blitzkrieg, Ideology, and Atrocity (University Press of Kansas, 2003).
• Maria Wardzyńska, Był rok 1939: Operacja niemieckiej policji bezpieczeństwa w Polsce. Intelligenzaktion (Instytut Pamięci Narodowej, 2009).
• Anna M. Cienciala, Natalia S. Lebedeva and Wojciech Materski, eds., Katyn: A Crime Without Punishment (Yale University Press, 2007).
• Jan T. Gross, Revolution from Abroad: The Soviet Conquest of Poland’s Western Ukraine and Western Belorussia (Princeton University Press, 1988; expanded ed. 2002).
• Jerzy B. Cynk, The Polish Air Force at War: The Official History, 1939–1943 (Schiffer, 1998); Michael Alfred Peszke, The Polish Navy 1918–1945 (Hippocrene, 1999).
• Władysław Kozaczuk, Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two, ed. and trans. Christopher Kasparek (University Publications of America, 1984); Gordon Welchman, The Hut Six Story (McGraw-Hill, 1982).
• Jan Karski, Story of a Secret State (Houghton Mifflin, 1944); Polish History Museum, “Jan Karski: The Mission,” record of the conversation with President Roosevelt.
• Karl-Heinz Frieser, The Blitzkrieg Legend: The 1940 Campaign in the West (Naval Institute Press, 2005).
• Polskie Siły Zbrojne w II Wojnie Światowej, vol. 1, Kampania wrześniowa 1939 (Instytut Historyczny im. gen. Sikorskiego, London, 1951–86).
• Adolf Hitler, Reichstag speech of 6 October 1939, English text at ibiblio (casualty figures).
• U.S. House of Representatives, Select Committee to Conduct an Investigation of the Facts, Evidence, and Circumstances of the Katyn Forest Massacre, Final Report (82nd Congress, H. Rept. 2505, 22 December 1952); East Carolina University, “Congress Investigates the Katyn Forest Massacre”; Moscow Times, “Secret Memos Show U.S. Hushed Up Katyn Crime” (10 September 2012).
• Institute of National Remembrance (IPN), “Scythes on planes” (the Kościuszko Escadrille and its badge).
• Museum of Siberian Memory, Białystok, “10.02.1940: They came at dawn for the first time”; dzieje.pl (Polish History Museum portal), on the Katyn day of remembrance.
• Museum of the Second World War in Gdańsk, muzeum1939.pl; United States Holocaust Memorial Museum, Holocaust Encyclopedia, articles on Warsaw, Łódź and the German invasion of Poland.
• Wikipedia: “Invasion of Poland”, “Soviet invasion of Poland”, “Occupation of Poland (1939–1945)”, “General Government”, “German war crimes during the invasion of Poland”, “Intelligenzaktion”, “Piaśnica massacres”, “Palmiry massacre”, “Sonderaktion Krakau”, “Piotrków Trybunalski Ghetto”, “Katyn massacre”, “Madden Committee”, “Polish government-in-exile”, “Polish Army in France”, “Polish Air Forces in France and Great Britain”, “No. 303 Polish Fighter Squadron”, “Polish Underground State”, “Museum of the Second World War”, “Bombing of Wieluń”, “Katyń Memorial (Jersey City)”, and biographies of Jan Karski, Witold Urbanowicz, Josef František and Marian Rejewski.

Photographs: German and Polish photographs of 1939–40 from the Polish National Digital Archive (Narodowe Archiwum Cyfrowe) and postwar Polish publications, a Soviet photograph of 1939 and a 1943 Katyn exhumation photograph published by the Polish government in exile, all public domain; modern photographs by Marcin Drewa (CC BY-SA 3.0 PL), Przemysław Jahr (public domain), Andrzej Otrębski and Fallaner (CC BY-SA 4.0); all via Wikimedia Commons. Insignia shown on cards are original illustrations, not official emblems.