of the Soviet Union. The British historian A. J. P. Taylor wrote in 1945 that National Socialism was inevitable because the Germans wanted "to repudiate the equality with the peoples of (central and) eastern Europe which had then been forced upon them" after 1918. During Stalin's Great Terror in the Soviet Union, a major ethnic cleansing operation, known as the Polish Operation, took place from about 25 August 1937 through 15 November 1938. According to Soviet NKVD archives, 111,091 Poles, and people accused of ties with Poland, were executed, and 28,744 were sentenced to Gulag labor camps, for a total of 139,835 Polish victims. This number constitutes 10 per cent of the officially persecuted persons during the entire Yezhovshchina period, with confirming NKVD documents. The prosecuted Polish families were accused of anti-Soviet activities. Outside the Germans and Russians, the Lithuanians also developed a very strong anti-Polish hatred, partly due to historical grievances. For the Lithuanians, the Polish–Lithuanian War of 1920, which costed the capital Vilnius to be on Polish hand, cemented anti-Polish sentiment. Virtually throughout the inter-war, anti-Polish had been omnipresent in Lithuania, and Polish minority in Lithuania faced a very harsh repression by the Lithuanian authorities. The 1938 Polish ultimatum to Lithuania led to the establishment of relations, but it remained extremely difficult as Lithuania still refused to accept Vilnius as part of Poland. Ukrainians were also another people with strong anti-Polish hostility. The Polish–Ukrainian War of 1919 resulted in Ukraine crippled militarily and, though Poland did assist Ukraine in the eventual conflict against the Bolsheviks, but was unable to prevent an eventual occupation by the Soviets. This had led to enmity against Poland by Ukrainian nationalists, which resulted in the establishment of Organization of Ukrainian Nationalists and the beginning of Ukrainian problem in Poland. Assassinations of Polish officials by Ukrainian nationalists became increasingly frequent from 1930s onward. Invasion of Poland and World War II Nazi propagandists stereotyped Poles as nationalists in order to portray Germans as victims and justify the invasion of Poland; the Gleiwitz incident was a Nazi false flag to show that Germany was under Polish attack, and the killing of Germans by Poles in Bromberger Blutsonntag and elsewhere was inflated to 58,000 to increase German hatred of Poles and justify the killing of Polish civilians. In October 1939, Directive No.1306 of Nazi Germany's Propaganda Ministry stated: "It must be made clear even to the German