Wladyslaw Sikorski

After the German invasion of Poland, Sikorski was appointed prime minister of the Polish government-in-exile on September 30, 1939, in Paris. He also served as Commander-in-Chief of the Polish Armed Forces. He led the exiled government throughout most of World War II.

Sikorski signed the Sikorski-Maisky Agreement with the Soviet Union on July 30, 1941, after the German invasion of the USSR. The agreement restored diplomatic relations, annulled the 1939 partition of Poland, and allowed for the formation of a Polish army in the Soviet Union under General Anders.

In April 1943, German forces announced the discovery of mass graves of Polish officers in the Katyn Forest. Sikorski requested an International Red Cross investigation, which led to a break in diplomatic relations with the Soviet Union on April 25, 1943, as the USSR denied responsibility.

Sikorski died in a plane crash at Gibraltar on July 4, 1943, shortly after takeoff. The crash killed all 16 passengers and crew, including his daughter. The cause remains disputed, with theories ranging from accident to Soviet or British assassination. His death was a major blow to the Polish government-in-exile.