Western Ukraine – the beginning of the Sovietisation (September–December1939). From the Perspective of the Ukrainian Historician On 17 September 1939 the Red Army attacked eastern Poland. On 28 September the USSR and Germany signed a pact which delineated, among others, a new border between Polish territories occupied by the two countries. The Soviets occupied the territory east of the San, Bug, Narew and Pisa Rivers. The official names for the territory were: Western Ukraine and Western Belarus. Lithuania was also included in their zone of influence. Functionaries of the communist party and security service came to Poland together with the Red Army. They were tasked to gain full control over the occupied territory. The Soviet security service commenced arrests of those accused of anticommunist activity, Polish administration representatives, the intelligentsia, and the so-called “enemies of the people” i.e. land owners and entrepreneurs. Tragic was the fate of the Polish POWs detained in special camps. The Soviets began organizing their own local administration. They introduced a new political system. They forbade the activity of the political parties and social organizations, and new ones following the Soviet model were set up in their place. There were also radical socio-economic changes. In October 1939 a Soviet-controlled election to the People’s Assembly of Eastern Ukraine was held. The deputies adopted a declaration unifying the territory of Eastern Ukraine with that of the Ukrainian Soviet Social Republic. In November the Polish territory was incorporated into the USSR. The inhabitants of the western districts of Ukraine were granted Soviet citizenship. Wołodymyr Baran The Sovietization process was quite intensive and was carried out on a massive scale. It influenced all areas of life, including the political and socio-economic systems as well as the spiritual and cultural spheres. Such a radical transformation had severe consequences for millions of people. On 17 September 1939 the Red Army attacked eastern Poland. On 28 September the USSR and Germany signed a pact which delineated, among others, a new border between Polish territories occupied by the two countries. The Soviets occupied the territory east of the San, Bug, Narew and Pisa Rivers. The official names for the territory were: Western Ukraine and Western Belarus. Lithuania was also included in their zone of influence. Functionaries of the communist party and security service came to Poland together with the Red Army. They were tasked to gain full control over the occupied territory. The Soviet security service commenced arrests of those accused of anticommunist activity, Polish administration representatives, the intelligentsia, and the so-called “enemies of the people” i.e. land owners and entrepreneurs. Tragic was the fate of the Polish POWs detained in special camps. The Soviets began organizing their own local administration. They introduced a new political system. They forbade the activity of the political parties and social organizations, and new ones following the Soviet model were set up in their place. There were also radical socio-economic changes. In October 1939 a Soviet-controlled election to the People’s Assembly of Eastern Ukraine was held. The deputies adopted a declaration unifying the ter- ritory of Eastern Ukraine with that of the Ukrainian Soviet Social Republic. In November the Polish territory was incorporated into the USSR. The inhabitants of the western districts of Ukraine were granted Soviet citizenship. The Sovietization process was quite intensive and was carried out on a massive scale. It influenced all areas of life, including the political and socio-economic systems as well as the spiritual and cultural spheres. Such a radical transformation had severe consequences for millions of people.