World War 2, a global conflict that reshaped the 20th century, began in September 1939. But the question of when and why did World War 2 start is rooted in a series of escalating events primarily driven by Adolf Hitler’s ambitions and miscalculations. By early 1939, the German dictator was determined to invade and occupy Poland, a move that ultimately triggered the outbreak of global hostilities.
Poland’s strategic location in Europe meant it had secured guarantees of military support from both France and Britain in the event of German aggression. Despite these warnings, Hitler pressed forward with his plans for invasion. However, he first needed to secure his eastern flank and prevent potential Soviet intervention. This led to a crucial, and surprising, diplomatic maneuver: the German-Soviet Nonaggression Pact.
Signed in Moscow on August 23-24, 1939, this pact was ostensibly a non-aggression agreement. However, a secret protocol within the pact revealed a more sinister agreement: Poland was to be divided between Germany and the Soviet Union. Germany would seize the western third, while the Soviet Union would occupy the eastern two-thirds. This cynical agreement removed the immediate threat of Soviet opposition to Hitler’s invasion of Poland.
With the Soviet Union neutralized, Hitler initially set the invasion date for August 26th. However, the signing of a formal treaty of mutual assistance between Great Britain and Poland on August 25th gave him pause. This treaty solidified earlier, less formal agreements and signaled stronger Western resolve. Hitler briefly postponed the invasion, but remained determined to disregard diplomatic efforts from Western powers aimed at preventing war.
Ultimately, Hitler’s ambition to expand German territory and power outweighed any deterrents. On August 31, 1939, at 12:40 pm, he issued the final order to commence hostilities against Poland at 4:45 am the following morning. The invasion of Poland began as ordered on September 1, 1939.
This act of aggression finally forced the hands of Poland’s allies. Great Britain and France, honoring their pledges, declared war on Germany. Britain declared war at 11:00 am on September 3rd, followed by France at 5:00 pm on the same day. With these declarations, the world was plunged into World War II, a conflict ignited by Hitler’s invasion of Poland and the failure of diplomacy to prevent it.
