The invasion of Poland by Nazi Germany on September 1, 1939, marked the beginning of World War II. It was a result of escalating tensions, aggressive expansionist policies by Germany, and failing diplomatic efforts to prevent conflict.

Source A: Excerpt from a historical analysis

'Germany’s invasion of Poland was driven by Adolf Hitler’s desire for territorial expansion and the need to secure lebensraum (living space) for the German people.' Provenance: Modern history textbook, 2005.

Many historians agree that several factors led to the invasion of Poland. These include Hitler’s desire for territorial expansion, the policy of appeasement by Britain and France, and the failure of diplomatic negotiations.

Source B: Excerpt from a historian’s commentary

'The failure of appeasement and the aggressive policies of Nazi Germany created a situation where invasion seemed inevitable.' Provenance: Modern history journal, 2010.

The invasion of Poland led Britain and France to declare war on Germany on September 3, 1939. It marked the start of World War II, which would involve many nations and lead to widespread destruction.

Source C: A historical account

'The invasion triggered a global conflict that changed the course of history, leading to millions of deaths and significant geopolitical shifts.' Provenance: History textbook, 2012.

The invasion of Poland had lasting effects, including the redrawing of borders in Europe, the rise of totalitarian regimes, and the reshaping of international relations. It also set the stage for the Cold War.

Source D: A modern historical perspective

'The invasion not only initiated WWII but also contributed to the long-term division of Europe and the emergence of superpower rivalry.' Provenance: Modern history analysis, 2018.