Formation of UK-Poland Alliance

Date: August 25, 1939 • Location: Warsaw, Poland

This milestone marked the outbreak and beginning of this historic period, which spanned 1939–1945.

The United Kingdom and Poland form a military alliance in which the UK promises to defend Poland in case of invasion by a foreign power.

The Second Polish Republic, officially known at the time as the Republic of Poland, was the Polish state that existed between 7 October 1918 and 6 October 1939 after being established in the final stage of World War I. The Second Republic was taken over in 1939 on the eve of its twenty-first anniversary, after it was invaded by Nazi Germany, the Soviet Union, and the Slovak Republic, marking the beginning of the European theatre of the Second World War. The Polish government-in-exile was established in Paris and later London after the fall of France in 1940.