East Polish Soviet Socialist Republic,[lower-alpha 1] abbreviated to East Polish SSR,[lower-alpha 2][1][2] also known as the Republic of Eastern Poland,[lower-alpha 3][2] was a proposition to establish a constituent republic of the Soviet Union, from the part of the territory of Lithuanian SSR and Byelorussian SSR. Its territory was planned to include the area with the majority of Polish population, including the Vilnius Region (with or without the city of Vilnius) and area around the city of Grodno. The idea emerged in early 1990, during the dissolution of the Soviet Union.[3][1][2]