What happened August 1939 AD

Accordingly, on 22 August 1939 Hitler ordered a military mobilization against Poland.

The Soviet Union signed a non-aggression pact with Nazi Germany on 23 August 1939.

The situation reached a general crisis in late August as German troops continued to mobilize against the Polish border. On 23 August, when tripartite negotiations about a military alliance between France, the United Kingdom and Soviet Union stalled, the Soviet Union signed a non-aggression pact with Germany. The Treaty of Non-Aggression between Germany and the Union of Soviet Socialist Republics was a non-aggression pact between Nazi Germany and the Soviet Union that enabled those two powers to divide-up Poland between them.

Hitler ordered the attack to proceed on 26 August, but upon hearing that the United Kingdom had concluded a formal mutual assistance pact with Poland, and that Italy would maintain neutrality, he decided to delay it.

Contrary to predictions that Britain would sever Anglo-Polish ties, Britain and Poland signed the Anglo-Polish alliance on 25 August 1939.

The German army, the Wehrmacht, was accompanied by seven SS Einsatzgruppen ("special task forces") and an Einsatzkommando, numbering altogether 3,000 men, whose role was to deal with "all anti-German elements in the hostile country behind the troops in combat". Most of the Einsatzgruppen commanders were professionals; 15 of the 25 leaders had PhDs.

On 29 August, Hitler demanded that a Polish plenipotentiary immediately travel to Berlin to negotiate the handover of Danzig, and to allow a plebiscite in the Polish Corridor in which the German minority would vote on secession.

The Poles refused to comply with the German demands, and on the night of 30–31 August in a stormy meeting with the British ambassador Neville Henderson, Ribbentrop declared that Germany considered its claims rejected.