Lecture given by Serhii Plokhii, Mykhailo S. Hrushevsky Professor of Ukrainian History, Harvard. After the end of the Yalta Conference in February 1945, a special envoy of President Franklin Delano Roosevelt, Edward J. Flynn, left the Crimea for Moscow to meet with Stalin, Molotov and the newly elected patriarch of the Russian Orthodox Church to discuss the treatment of religion by the communist authorities. Less than a month after Flynn concluded his talks in Moscow and went to Rome to see the pope, the Soviet authorities arrested the entire hierarchy of the Ukrainian Greek Catholic Church in the newly acquired western provinces of the Soviet Union. In the following year the five-million-strong church, which had been under the jurisdiction of Rome, was liquidated, its faithful persecuted and forced underground. Did these acts of violence have anything to do with the decisions made at Yalta and Flynn's trip to Moscow? The paper engages this and other related questions, elucidating previously unknown aspects of the division of Europe into spheres of influence. It draws on a chapter of Serhii Plokhy's book, Yalta: The Price of Peace, released in the United States earlier this year.