"Central Europe had a mirror-image quality after September 1939. For it had not only been Hitler who had ordered his troops to invade Poland. Under the terms of the Nazi-Soviet Pact signed in Moscow that August, Josef Stalin had done the same, on September 17. To conservatives like Duff Cooper or Evelyn Waugh, it seemed a moment of revelation, laying bare the essential identity of the two totalitarian systems, National Socialism and 'socialism in one country'. The signatories themselves appreciated the irony of their partnership. When he flew to Moscow to sign the pact, Ribbentrop had joked that Stalin would 'yet join the Anti-Comintern Pact', Hitler and Mussolini's anti-Communist alliance. Nevertheless, the partition of Poland did not produce exactly identical totalitarian twins. The Soviet zone of occupation was in many respects a mirror image of the German zone but, as with a true mirror image, right and left were transposed."