On April 13, 1943, the German forces occupying western Russia announced that they had discovered mass graves of Polish officers in the Katyń forest near Smolensk, causing a diplomatic rift between the Polish government-in-exile in London and the Soviet Union, which denied responsibility.
After the joint invasion and occupation of Poland by Nazi Germany and the Soviet Union in September 1939, the country was divided between the two powers, in accordance with the Molotov–Ribbentrop Pact.
With Soviet forces occupying the eastern half of Poland, tens of thousands of Polish military personnel fell into Soviet hands and were interned in prison camps inside the Soviet Union.
Thousands of Polish officers found dead in Katyń
When the Germans launched Operation Barbarossa and invaded the Soviet Union in June 1941, the Polish government-in-exile in London and the Soviet government agreed to cooperate against Nazi Germany and to form a Polish army on Soviet territory.
But when Poland requested that the thousands of Polish prisoners of war be released, the Soviet government replied that most of those prisoners had escaped to Manchuria and could not be located.
The fate of the missing prisoners remained a mystery.
Then, on April 13, 1943, Berlin announced that its troops occupying western Russia had uncovered a ditch in the Katyń forest near Smolensk “in which the bodies of 3,000 Polish officers were piled up”, before accusing the Soviets of carrying out the massacre. The Soviet government immediately claimed that the Poles had been killed by the invading German army which had overrun the area in August 1941.
Seeing the discovery as an excellent propaganda tool to drive a wedge between Poland, the Western Allies, and the Soviet Union, Joseph Goebbels, intent on proving the Soviets were behind the massacre, brought in the so-called International Katyn Commission, led by world-class pathologists, to investigate the massacre.
The international investigations concluded that the Soviet Union was indeed responsible for the massacre after finding firm physical evidence that the killings took place in early 1940, at a time when the area was still under Soviet control. But the Soviets continued to deny their responsibility and broke off diplomatic relations with the Polish government in London.
The Katyń Massacre left a deep scar in Polish-Soviet relations during the remainder of the war and afterward, as the Soviet leaders kept insisting for decades that the Polish officers found at Katyń had been killed by the Germans – an explanation which was accepted without protest by the successive Polish communist governments until the late 1980s.
Truth about Katyń emerges in the 1990s
But in 1992, the Russian government released documents proving that the Soviet Politburo and the NKVD had been responsible for the massacre and subsequent cover-up, revealing that there may have been more than 20,000 victims.
And in 2000, a memorial was opened at the site of the killings in Katyń. Russia and Poland remain however divided on the legal description of the crime.
Of the tens of thousands killed near Katyń, about 8,000 were officers imprisoned during the 1939 Soviet invasion of Poland, another 6,000 were police officers, and the remaining 8,000 were Polish intelligentsia, including landowners, factory owners, lawyers, officials, and priests.
On April, 10, 2010, an aircraft carrying Polish President Lech Kaczyński and other high-ranking Polish officials to a ceremony marking the 70th anniversary of the Katyń massacre crashed in Smolensk, killing all 96 aboard… casting Russia as Warsaw’s untrustworthy neighbour once more and plunging Poland back into a deep suspicion of the Kremlin.
Find out more about Central European history in our On this Day series.