Soviet-backed Second East Turkestan Republic was formed in northern Dzungaria, while the Republic of China retained control of southern Xinjiang. Both states were annexed by the People's Republic of China in 1949. Soviet era (1918–1991) After being conquered by Bolshevik forces, Soviet Central Asia experienced a flurry of administrative reorganisation. In 1918 the Bolsheviks set up the Turkestan Autonomous Soviet Socialist Republic, and Bukhara and Khiva also became SSRs. In 1919 the Conciliatory Commission for Turkestan Affairs was established, to try to improve relations between the locals and the Communists. New policies were introduced, respecting local customs and religion. In 1920, the Kirghiz Autonomous Soviet Socialist Republic, covering modern Kazakhstan, was set up. It was renamed the Kazakh Autonomous Soviet Socialist Republic in 1925. In 1924, the Soviets created the Uzbek SSR and the Turkmen SSR. In 1929 the Tajik SSR was split from the Uzbek SSR. The Kyrgyz Autonomous Oblast became an SSR in 1936. These borders had little to do with ethnic make-up, but the Soviets felt it important to divide the region. They saw both Pan-Turkism and Pan-Islamism as threats, which dividing Turkestan would limit. Under the Soviets, the local languages and cultures were systematised and codified, and their differences clearly demarcated and encouraged. New Cyrillic writing systems were introduced, to break links with Turkey and Iran. Under the Soviets the southern border was almost completely closed and all travel and trade was directed north through Russia. During the period of forced collectivisation under Joseph Stalin at least a million persons died, mostly in the Kazakh SSR. Islam, as well as other religions, were also attacked. In the Second World War several million refugees and hundreds of factories were moved to the relative security of Central Asia; and the region permanently became an important part of the Soviet industrial complex. Several important military facilities were also located in the region, including nuclear testing facilities and the Baikonur Cosmodrome. The Virgin Lands Campaign, starting in 1954, was a massive Soviet agricultural resettlement program that brought more than 300,000 individuals, mostly from the Ukraine, to the northern Kazakh SSR and the Altai region of the Russian SFSR. This was a major change in the ethnicity of the region. Similar processes occurred in Xinjiang and the rest of Western China where the PRC quickly established control from the Second East Turkestan Republic that controlled northern Xinjiang and the Republic of