This Sunday marks 80 years since Nazi Germany’s invasion of Poland and the commonly recognized start of World War II. Though the war was fought nearly a century ago and many of the countries that participated in it no longer technically exist, the war is remembered very differently across Europe and selective interpretations of historical memory continue to serve modern nationalist narratives and objectives.

A week before the Nazi invasion of Poland, on August 23rd, Germany and the Soviet Union signed the Molotov-Ribbentrop Pact: a mutal non-agression treaty that mandated peace between both powers and carved out “spheres of influence” for each of them in Europe. Germany would eventually break the pact by invading the Soviet Union two years later. Though the pact was a secret of the Soviet Union until 1989, the Russian State Archives opened a public exhibition of the original treaty on August 23rd of this year in Moscow.

The exhibition comes as Russia and many Eastern European nations that were annexed or occupied by the Soviet Union during World War II confront differing interpretations of the pact’s necessity, and of the events that followed its signing. Russian Foreign Minister Sergei Lavrov announced at the exhibition’s opening that, given the circumstances of late 1930’s European politics, “the Soviet Union was forced on its own to ensure its national security and signed a nonaggression pact with Germany.” Many nations such as Poland and Ukraine that found themselves within the sphere of influence of either Nazi Germany or the Soviet Union and were annexed or occupied by these powers have preserved a very different memory of history and the relative necessity of signing the pact.

With us to talk more about how selective memories of the pact and other aspects of World War II continue to define modern national identities is Timothy Snyder, Professor of History at Yale University and author most recently of The Road to Unfreedom: Russia, Europe, America. He also wrote On Tyranny: Twenty Lessons from the Twentieth Century.