By the early part of 1939 the German dictator Adolf Hitler had become determined to invade and occupy Poland. Secret negotiations led on August 23–24 to the signing of the German-Soviet Nonaggression Pact in Moscow. In a secret protocol of this pact, the Germans and the Soviets agreed that Poland should be divided between them, with the western third of the country going to Germany and the eastern two-thirds being taken over by the USSR.
On August 31, 1939, Hitler ordered hostilities against Poland to start the next morning. The invasion began as ordered. In response, Great Britain and France declared war on Germany on September 3. World War II had begun. www.britannica.com/event/World-War-II,

Further debunking: theins.ru/history/70515,