This list should only include links to events that already have their own pages on Wikipedia. More detailed entries can be listed in the detailed timeline.
Links to pages that are also "key events" (see above) are depicted in bold.
August
17 August
Following German advances that started in early 1939, Soviet Foreign Commissar Vyacheslav Molotov, after the failure to find a diplomatic agreement with the Allies, agrees to specific diplomatic talks with the Germans.[1]: 78
Following intense German-Soviet negotiations, the Molotov–Ribbentrop Pact is finalized (to be publicized on 24 August). The two powers agree to a broad economic exchange and to mutual military non-aggression. In a secret additional protocol, the two powers approve of each other's expansionist ambitions in Central Eastern Europe. Poland is divided (along the line of the San, Vistula and Narew rivers) into a German and Soviet sphere of influence.[1]: 78f.
25 August
Orders are issued to German forces to commence the invasion on 26 August.[2]: 103
The scheduled invasion (see 25 August) is called off at the last possible moment to buy the Germans more time.[4]: 16
The cancellation of the invasion orders fail to reach all German units in time; German saboteurs carry out a bombing attack at the Jablunkov Pass in what becomes known as the Jabłonków incident.[5]: 47
Italian dictator Benito Mussolini sends a long list of equipment and support requests to German dictator Adolf Hitler to create an excuse for Italy to stay neutral in the imminent war.[6]: 160f.
28 August
The Polish inspector-general requests the President to issue orders for general mobilization.[7]: 110
Polish general mobilization orders are called off under pressure by the Western Allies.[7]: 110
Polish military leaders are ordered to move their troops into their jumping-off points.[7]: 110
30 August
Polish general mobilization ordered again, to go into effect on 31 August.[7]: 110
The Polish government announces that it has carried out defensive mining operations in its territorial waters.[5]: 49
The Polish navy launches the Peking Plan to evacuate its three main destroyers to the United Kingdom.[2]: 103f.
31 August
Hitler gives final approval to the invasion, to begin on the morning of 1 September; SS instructed to executed "Operation Himmler" to create various pretexts for invasion.[2]: 106f.
In the night from 31 August to 1 September, the SS instigates a false flag attack ("Gleiwitz Incident") against Gleiwitz Radio Station and sends broadcasts in the Polish language to create a pretext for German invasion.[9]: 668
Germany issues a last-minute ultimatum to Poland (but does not provide either Poland or the United Kingdom with enough time to formulate diplomatic responses).[1]: 83
Around 04:30, Stukas of III./KG1 attack Polish positions at Tczew bridge in the unsuccessful attempt to preempt the demolition of the bridge by Polish forces.[2]: 107
German 4th Army advances into the "Danzig Corridor"; a cavalry counterattack ("Charge at Krojanty") by the 18th Uhlans gives birth to the myth of Polish cavalry attacking German tanks.[12]: 509f.
German public reactions to the outbreak of war are less than enthusiastic.[15]: Ch.III
Soviet Union allowed the Germans to use radio stations in Minsk to enable them to covertly instruct German pilots bombing Poland.[16]
2 September
Polish Army soldier holding last remaining part of destroyed German bomber Heinkel He 111 in Warsaw, September 1939 (Kodachrome photo).
German naval forces under Günter Lütjens exchange fire with Wicher, Gryf and Polish coastal batteries; Leberecht Maaß (Ger.) damaged, Wilk (Pol.) damaged by bombs, Mazur (Pol.) sunk by Stukas of the 1st Air Division.[17]: 12
German 3rd Army regroups after surprising Polish resistance in the northern sector (during the Battle of Mlawa); Panzer Division Kempf assigned to Wodrig Corps to shift the gravity of attack.[2]: 113
The Luftwaffe bombed a train with civilian refugees from Krotoszyn in Koło, killing 300 people.[21][22]
3 September
During the withdrawal of Polish troops from Bydgoszcz, local Germans opened fire on Polish soldiers and civilians, forcing them into a defensive battle in which several hundred people were killed on both sides. The event was referred to as the Bloody Sunday by the propaganda of Nazi Germany, with number of German victims upped to 58,000 by German propagandists.[23]: 26
Soviet Defense CommissarVoroshilov orders seven military districts in the western Soviet Union to increase their combat readiness.[26]: 125
4 September
Schleswig-Holstein intensifies its bombardment (supported through 21cm howitzers brought from East Prussia) against Polish defenders at Westerplatte as the Battle of Westerplatte continues.[27]: 31
German 8th Army captures five bridges across the Warta river intact and begins its river crossing.[13]: 122f.
Rydz-Śmigły orders a counterattack by Wyszków Operational Group with 1st Legions Infantry Division and 33rd Infantry Division at 18:15, though his order does not reach the Operational Group's commander Kowalski until 06:00 the next day.[14]: 247
During the night of 5/6 September, the Polish defenders of Różan evacuate their positions.[14]: 248
6 September
Wyszków Operational Group begins its counterattack (as ordered on 5 September) towards Pułtusk against I Corps; 1st Legions Infantry Division and 61st Infantry Division clash.[14]: 247
Corps Wodrig forces the Germans' way across the Narew river; the corps subsequently wastes time with preparations to attack Różan (already evacuated by Polish defenders during the night of 5/6 September).[14]: 248
XXII Corps severs the line between Warsaw and Częstochowa.[32]: 109
The Polish air force attempts a general offensive and musters 164 sorties with 13 victories and nine planes lost. In the evening, orders are given to move all remaining Polish fighters to Lublin, where 88 fighters are subsequently formed into the newly-improvised Pursuit Brigade.[14]: 160
The Polish government and its accredited ambassadors evacuate Warsaw and relocate to Lublin.[32]: 102
Poles evacuate the arms factory in Starachowice to Kowel; Germans attack the Wanacja suburb of Starachowice, and then murder over 20 civilians.[33]
German troops perpetrated a massacre of Polish POWs, including 19 officers, in Moryca and Longinówka, and massacres of 56 Polish civilians in Będzin and Uniejów.[30][34]
During the night of 6/7 September, the Wyszków Operational Group's progress is significantly hampered by logistical chaos when the 33rd and 41st Infantry Divisions become hopelessly entangled with each other, causing mass confusion among the troops.[14]: 247
7 September
At 04:15 in the morning, Schleswig-Holstein opens the final bombardment against Westerplatte, whose defenders surrender around 10:15.[27]: 32
Decision of the German Ministry of the Interior to dissolve the Union of Poles in Germany and close Polish minority schools, printing houses, and financial and cooperative institutions.[38]
8 September
German forces reach the outskirts of Warsaw;[15]: Ch.III probing attacks by the 4th Panzer Division, which had judged Warsaw to be undefended the previous day, meet heavy Polish resistance in the Ochota suburb.[12]: 308
At 5:30 a.m., German forces launched an assault on Kłecko, capturing it in the evening, suffering heavy losses in the face of fierce Polish defense.[39]
In preparation for the Soviet invasion of Poland, the NKVD ordered the establishment of operational groups, which would commit massacres of Polish POWs and civilians.[42]
9 September
Public execution of Polish civilians in Bydgoszcz on 9 September 1939
4th Panzer Division repeats its attack against Warsaw; Panzer Regiment 35 suffers heavy casualties, leading to the eventual recall of 4th Panzer Division from the Warsaw sector.[12]: 308f.
The German 8th Army captures Łódź, and subsequently advances against a concentration of Polish forces southwest of Warsaw that was giving XVI Corps of 10th Army significant trouble.[7]: 123
German troops perpetrated massacres of around 80 Polish civilians in Kłecko, Mielno, Orło and Pniewo, and massacres of over 260 Jews in Będzin, Sławków and Wyszków.[43]
During the night of 9/10 September, the Poznan Army attempts a breakout attempt towards the south of Łódź and strikes the flank of the German 8th Army (primarily the 30th Infantry Division),[13]: 127 achieving operational surprise against the Germans.[44]: 11
German 14th Army forces its way across the river San on both sides of Przemyśl. The gros of the 11th Polish Infantry Division is trapped inside Przemyśl.[46]: 208f.
Poland's submarines are ordered via radio to attempt the breakout to British waters, or to otherwise seek internment in neutral ports.[17]: 15
II Corps approaches Modlin Fortress, where parts of the corps settle in to besiege the defenders, while the main body of the corps advances towards Dębe.[7]: 123
The German 207th Infantry Division breaks Polish positions at Reda and forces the Land Coastal Command to withdraw to Kępa Oksywsk.[14]: 168f.
Wilhelm Canaris warns Wilhelm Keitel that the SS is making urgent preparations for imminent mass executions in German-occupied Poland; Keitel responds that these executions are approved by Hitler and that the Wehrmacht must tolerate them.[51]: 62
4th Panzer Division attempts to cross the Bzura river to attack the Poznan Army in its German-encircled position, but is beaten back; Panzer Regiment 36 and SS Leibstandarte are temporarily trapped by Polish forces.[12]: 309
German troops perpetrated massacres in Bocheń, Guźnia and Retki, killing 49 Polish civilians.[59]
Order No. 005 of the Soviet Minsk Military District is read out to Soviet troops, promising them the "liberation of Ukrainian and Belarussian workers from Polish landowners and capitalists".[26]: 125
17 September
In the Soviet invasion of Poland, the Red Army intervenes in the German-Polish war on the German side, beginning its advance towards the German-Soviet demarcation line agreed in the Molotov-Ribbentrop Pact.[26]: 125
Polish defense of Sarny against the Soviets begins.[60]
Rydz-Śmigły instructs Polish units in eastern Poland to avoid combat with the Red Army as far as possible and to withdraw towards the national frontiers with Romania and Hungary.[26]: 126f.
XV Corps (of 10th Army) crosses the Warsaw—Sochaczew road and further tightens the chokehold around Warsaw.[7]: 124
The main clashes of the Battle of the Bzura cease; OKH reports 120,000+ Polish prisoners from a total of 19 divisions and three cavalry brigades.[7]: 124
Following Soviet pressure against the Estonian government, Orzel leaves Tallinn and begins its breakout towards the United Kingdom, which it would reach (without maps) on 14 October.[17]: 16
Germans perpetrated a massacre of some 300 Poles, including POWs and refugees, in Śladów.[62]
19 September
Soviet troops enter Wilno, 19 September
German forces complete the encirclement of Warsaw, ending what the Germans would subsequently dub the "Eighteen Days Campaign".[63]: 132
Krakow Army attempts a breakout towards the Romanian frontier through Tomaszow Lubelski.[44]: 12
Pomorze Army and Poznan Army are forced to surrender.[15]: Ch.III
Army Group South is ordered to abort its attacks and to withdraw west of the Vistula-San line to make space for the advancing Soviets. The German siege of Lwów is aborted and left to the Soviets. A German attack against the city by XVIII Army Corps planned for 21 September is cancelled.[18]: 118
Clashes between Polish and Soviet forces at Grodno ("Battle of Grodno").[26]: 129
German troops carried out a massacre of 42 Polish POWs in Majdan Wielki.[65]
Polish garrison of Lviv unexpectedly attempts surrender to the withdrawing Germans;[18]: 118 occupation of Lviv is left to the Soviets, who take the city after an artillery bombardment.[67]: 83
Reinhard Heydrich issues a directive to begin the concentration of Poland's Jews in the major cities to prepare the formation of ghettos and to ease subsequent deportations to concentration camps.[51]: 62
Appointed German Kreisleiter called Polish municipal officials in Bydgoszcz to a supposed formal meeting in the city hall, from where they were taken to a forest near Bydgoszcz and exterminated.[74] He also ordered the execution of their family members to "avoid creating martyrs".[74]
27 September
Warsaw surrenders.[75]: 327 Polish general Tadeusz Kutrzeba meets with Johannes Blaskowitz to discuss the terms of surrender.[32]: 252
In the early morning, the 19th Uhlans are ambushed by a Soviet tank column, but manage to repel the initial assault.[32]: 250
26th Uhlans and 27th Uhlans are surprised by strong Soviet armored formations ("Battle of Władypol") and shatter. Small groups of survivors begin to fight their way to the Hungarian border, some 40km away.[32]: 250
Soviet-Polish battle at Szack; 52nd Rifle Division and 411th Tank Battalion forced in temporary retreats by Polish defenders.[26]: 130
Germany and the Soviet Union sign a Border and Friendship Treaty and adjust the frontiers of occupied Poland. The Soviet Union publicly blames the Western Allies for the continuation of the war.[77]: 233–236
Germans carried out the second mass execution, this time of 16 patients of the Kocborowo psychiatric hospital, at the Forest of Szpęgawsk.[73]
The Polish garrison of Modlin fortress surrenders at 08:00; the roughly 35,000 defenders (including 4,000 wounded) are released as agreed in the surrender agreement, though most officers are subsequently recaptured in the following weeks and detained in POW camps.[32]: 255
Around 02:00 at night, a Polish vanguard of the Border Protection Corps meets a column of Soviet tanks near Wytyczno and destroys four of them. As the BPC crosses the Bug river south of Włodawa to catch up with Independent Operational Group Polesie forces, a Soviet counterattack ("Battle of Wytyczno") commences in the early morning. General Wilhelm Orlik-Rückemann decides to break up his force into small units and send them into various directions. Several massacres are subsequently committed by the Soviet pursuers against Polish groups of soldiers.[32]: 259f.
After a final assault against Hel by the German Infantry Regiment 374 towards Hel, the Polish commander asks for an armistice around 14:00.[27]: 38
At 14:30, the German mineseeker M85 is sunk by the Polish submarine Zbik with 23 lives lost, sole Polish submarine victory of the campaign.[27]: 39
Ger. 10th Army is alerted to return to Germany to prepare operations against France.
Germans carried out a massacre of 64 Polish men, including ten boys under the age of 18, in Szczuczki.[78]
Polish Consul in Kyiv Jerzy Matusiński was summoned for supposed talks at the Representation Office of the People's Commissariat for Foreign Affairs, and then arrested by the Soviets, with his fate unknown to this day.[79]
2 October
Command of the Defenders of Poland (Komenda Obrońców Polski) Polish resistance organization founded in Warsaw.[80]
3 October
Gerd von Rundstedt becomes military commander in German-occupied Poland.[18]: 118
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