Nazi Germany's invasion of Poland in 1939 was characterized by mass murders of civilians and prisoners of war, attacks on undefended civilian targets, rapes, looting, destruction of property, and other severe violations of the international humanitarian law committed by German military, police, and paramilitary formations.
The advance of Wehrmacht units into Poland was accompanied by a wave of violence. In retaliation for alleged partisan attacks or resistance from Polish troops, German soldiers repeatedly burned villages and settlements, murdering their inhabitants. It is estimated that in September 1939, 434 or 476 Polish villages were destroyed. Massacres and retaliatory executions also took place in cities, particularly in Bydgoszcz and Częstochowa. War crimes against Polish prisoners of war occurred in all operational areas. In towns inhabited by Jews, German soldiers carried out so-called "swift pogroms", often involving mass killings, looting, and synagogue burnings. The Luftwaffe repeatedly targeted civilian sites, including undefended towns, hospitals, churches, historic buildings, as well as evacuation trains and refugees on the roads. The German army also faced serious disciplinary issues, leading to widespread looting and sexual violence.
Following the Wehrmacht's advance, the Einsatzgruppen carried out mass arrests and executions in newly occupied territories. Their victims were primarily members of the so-called Polish leadership class and Jewish civilians.
It is estimated that between 1 September and 25 October 1939, when military administration on occupied Polish territory was abolished, the Wehrmacht, SS, Ordnungspolizei, Volksdeutscher Selbstschutz, and other German formations carried out 714 executions, resulting in the deaths of approximately 16,000 civilians. Over 12,000 victims – nearly 75% – were murdered in September 1939 alone. At least 3,000 captured Polish soldiers were executed away from combat zones. Additionally, tens of thousands of civilians lost their lives due to German air raids and artillery shelling.
Origins
Adolf Hitler's plans regarding Poland For Adolf Hitler and other Nazi leaders, the war with Poland was not viewed as a conventional military conflict, but as an operation aimed at bringing about far-reaching territorial and demographic changes in Central and Eastern Europe. These intentions were not concealed from the highest commanders of the Wehrmacht. On 10 February 1939, even before the outbreak of the open crisis in Polish-German relations, Hitler delivered a speech to generals in which he stated that "the next war will have a purely ideological character, meaning it will be a national and racial war".
On 25 March 1939, Hitler told the Commander-in-Chief of the Army, General Walther von Brauchitsch, that "Poland will have to be destroyed in such a way that in the following decades it will not be considered as a political factor". Later, during a meeting with the highest Wehrmacht commanders on 23 May of the same year, he emphasized that the goal of the planned aggression would not be solely the recovery of Gdańsk and other territories of the former Prussian Partition, but the "expansion of living space in the East and securing food for our nation". He was not hiding that elements of the policy towards the conquered country would involve mass resettlements and the extensive use of forced labor. Additionally, on 14 August, in a conversation with Generals von Brauchitsch and Franz Halder, he stated that he intended to break Poland in a way deeper than a military defeat. These announcements raised no objections among the German general staff; their concerns were only about the possibility of a war with Western powers.
On 22 August 1939, the highest commanders of the Wehrmacht gathered at Hitler's summer residence in Obersalzberg. The meeting was secret, and note-taking was strictly forbidden. However, the speech Hitler delivered that day has been preserved in five versions. Admiral Wilhelm Canaris, whose notes are considered the most reliable, recorded Hitler's words, stating that the upcoming conflict would be a "war of annihilation" and its goal was the "total destruction of Poland". Hitler also allegedly ordered his generals:Be merciless! Be brutal! 80 million people must get what they deserve, and they deserve the assurance of their existence. The law is on the side of the stronger. We must act with the utmost severity.According to another version,Its credibility is sometimes questioned. However, on 25 August 1939, Admiral Wilhelm Canaris, in a conversation with General Franz Halder, expressed his "concern about the role of the Totenkopfverbände", which, according to Jochen Böhler, may indicate that these words were indeed spoken (). Hitler was quoted as having said:I have prepared, for now, on the East only, the Totenkopf units and ordered them to kill without mercy or pardon the men, women, and children of Polish descent and the Polish language. Only in this way will we gain the living space we need.
Attitude of Wehrmacht soldiers and commanders towards the people of Poland Jochen Böhler, analyzing the criminal behavior of Wehrmacht soldiers towards Polish civilians and prisoners of war in September 1939, concluded that it resulted from a combination of motivational, situational, and psychological factors. He points out the following:
Nazi indoctrination, to which soldiers were subjected both during basic training in the Wehrmacht and in institutions they encountered before starting active military service, such as the Hitler Youth, Sturmabteilung, Reich Labour Service, etc. Deeply rooted anti-Semitic, anti-Polish, and anti-Slavic prejudices and stereotypes, which were further reinforced by Nazi propaganda that exploited, among other things, the alleged persecution of the German minority in Poland. Exposure to the poor living conditions in Poland, which strengthened soldiers' prejudices, including the belief in the "civilizational inferiority" and "demoralization" of the local population. The consequence was insensitivity to their suffering and a reduction in resistance to the use of violence. points out in this context a letter from a certain non-commissioned officer, who did not perceive setting fire to thatched-roof rural cottages (described by him as "bedbug dwellings") as a reprehensible act. Contact with Eastern European Jews (Ostjuden), often orthodox practitioners of Judaism, who differed greatly in clothing and customs from German Jews, contributed to the intensification of anti-Semitic sentiments within the Wehrmacht. Lack of combat experience among most German soldiers, leading to excessive nervousness and aggression, which found expression in violence against POWs and civilians.
Anti-Polish and anti-Semitic prejudices were also reflected in instructions and directives given to soldiers before the war broke out. The German command expected, in particular, that the invading forces would have to deal with numerous acts of sabotage and active participation by the civilian population in combat actions. Such an attitude was based on both the experiences gained during the Silesian Uprisings and the deeply rooted fear of partisans in German military tradition,To some extent, it was also present in the Austrian military tradition, and its roots dated back to the Serbian campaign during World War I. These experiences may have had some influence on the actions of those Wehrmacht mountain units fighting in Poland, which originated from the former Austrian army (). dating back to the Franco-Prussian War.
In the Instruction on the Polish Way of Conducting War (Merkblatt über Eigenarten der polnischen Kriegsführung), issued by the Foreign Armies East Department on 1 July 1939, there were warnings that Poles were "fanatically stirred up" (for which "the Catholic clergy is usually responsible"), "kind treatment would quickly be seen as a sign of weakness", and Jews "see Germans as their personal enemies, but for money, they are capable of anything". This document also warned about possible acts of sabotage, including the destruction and poisoning of food supplies. In a directive issued by the Oberkommando der Wehrmacht, which was sent to divisional-level units in the last days of August 1939, it was warned that "cruelty, brutality, treachery, and lies are methods of combat that an enraged Pole uses instead of quiet strength". At the same time, a special order from the 8th Army command for rear services on 24 August 1939 recommended not to trust Poles and Jews living in the defeated areas, but to treat them as enemies accordingly.
The expected resistance of the civilian population was to be suppressed in an "energetic and ruthless" manner. On 9 August 1939, the Oberkommando des Heeres issued an order recommending that "as soon as the situation on the front allows", all able-bodied men of Polish and Jewish nationality aged 17 to 45 should be interned and treated as prisoners of war.
Warnings of possible partisan attacks were also issued at lower levels, including by the command of individual divisions and even regiments. For example, on the day of the outbreak of hostilities, the commander of the 20th Infantry Regiment of the 10th Infantry Division ordered his soldiers: "Do not be gullible, but treat every Polish citizen as a fanatical enemy who will fight you by all means! [...] Be ruthless to every partisan you encounter with a weapon in hand!".
As reality showed, these types of orders and warnings significantly increased the nervousness of inexperienced German soldiers, intensifying their readiness to use violence against civilians and POWs.
Operation Tannenberg
Preparations and objectives
On 22 May 1939, the so-called Zentralstelle II P was established in the Main Office of the Security Service (SD-Hauptamt). Its task was to register Germans living in Poland,Primarily with the aim of identifying potential informants (). Poles living in the Third Reich, as well as those Poles residing in Poland who had "distinguished themselves in national struggles" or were involved in promoting Polishness in Germany. It was assumed that the files of section II P would be "made available to a potential operational group". Information was also collected on Polish Jews, with the SD's Jewish Affairs Department (II 112) participating in this effort.
In July and August 1939, SS-Brigadeführer Werner Best – working closely with SD foreign intelligence chief Walter Schellenberg and using the departments subordinate to him in the Office of Administration and Law at the Main Office of the Sicherheitspolizei (Hauptamt Sicherheitspolizei), as well as Department I of the Gestapo (Gestapo Amt) – created the normative, personnel, and technical framework for the SD and Sicherheitspolizei operational groups (Einsatzgruppen), which were to operate behind each of the Wehrmacht armies participating in the invasion of Poland.
By the end of August 1939, five Einsatzgruppen had been formed, numbered from I to V. In early September, after the war had already begun, two additional operational groups were established: Einsatzgruppe VI and Einsatzgruppe zur besonderen Verwendung, along with an independent unit, Einsatzkommando 16. The actions carried out by the SD and security police in Poland were given the codename Tannenberg. The name Unternehmen "Tannenberg" (Operation Tannenberg) was also used for a special department within the Main Office of the Security Police, created to coordinate the actions of the Einsatzgruppen.