The Leningrad affair, or Leningrad case (, Leningradskoye delo), was a series of criminal cases fabricated in the late 1940s–early 1950s by Joseph Stalin in order to accuse a number of prominent Leningrad based authority figures and members of the All-Union Communist Party (Bolsheviks) of treason and intention to create an anti-Soviet organisation based in the city. This happened in the aftermath of the Siege of Leningrad during the war, the victorious end of which led to the mayor, his deputies and others who kept Nazi German forces out of the city earning fame and strong support as heroes all over the USSR. This in turn would lead to them becoming the target of Joseph Stalin's long established suppression of emerging popular figures deemed to be potential rivals or problems in the future. Preamble Moscow and Leningrad were two competing power centers in the Soviet Union. Researchers argue that the motivation behind the cases was Joseph Stalin's fear of competition from the younger and popular Leningrad leaders – who had been fêted as heroes following the city's siege. Stalin's desire to keep power was combined with his deep distrust of anyone from Leningrad from the time of Stalin's involvement in the Russian Revolution, Russian Civil War, execution of Grigory Zinoviev and the Right Opposition. In this earlier time, among Stalin's competitors from Leningrad who were also assassinated were two former leaders of the city, Sergei Kirov and Leon Trotsky, whose appointed subordinates continued to work in the city government for years after they left office. During the siege of Leningrad, the city leaders were relatively autonomous from Moscow. Survivors of the siege became national heroes, and leaders of Leningrad again gained much clout in the Soviet central government in Moscow. Events In January 1949 Pyotr Popkov, Alexey Kuznetsov and Nikolai Voznesensky organised a Leningrad Trade Fair to boost the post-war economy and support the survivors of the Siege of Leningrad with goods and services from other regions of the Soviet Union. The fair was attacked by official Soviet propaganda, and was falsely portrayed as a scheme to use the federal budget from Moscow for business development in Leningrad, although the budget and economics of such a trade fair were normal and legitimate and approved by State Planning Commission and the government of the USSR. Other accusations included that Kuznetsov, Popkov and others tried to re-establish Leningrad's historic and political importance