Polish People's Republic
The Polish People's Republic (, ) was a state in Central Europe that existed from 1947 to 1989, and the predecessor of the modern democratic Republic of Poland. With a population of approximately 37.9 million inhabitants near the end of its existence, it was the most populous state of the Eastern Bloc after the Soviet Union. Having a unitary Marxist–Leninist communist government, it was also one of the main signatories of the Warsaw Pact. The official capital since 1947 and largest city was Warsaw, followed by industrial Łódź and cultural Kraków.
Vistula Land
As the Russians retreated, the Central Powers occupied the area (1915); subsequently they proposed the establishment of the Kingdom of Poland (1916–1918). In the March 1918 Treaty of Brest-Litovsk, Russia (by then embroiled in a civil war), effectively ceded all Polish territories it had formerly possessed to the German Empire and Austria-Hungary.a Sources agree that after the fall of the January Uprising in 1864, the autonomy of Congress Poland was drastically reduced. However, they disagree on whether the state of the Kingdom of Poland (colloquially known as Congress Poland) was officially replaced by the Vistula land as a province of the Russian Empire, as many sources still use the term Congress Poland for the post-1864 period. The sources are also unclear as to when the Kingdom of Poland (or Vistula land) officially ceased to exist; some argue it ended with the assumption of control by the German and Austro-Hungarian occupying authorities; others, that it ended with the proclamation of the Regency Kingdom of Poland in 1916; finally, some argue that it occurred only with the creation of the independent Second Polish Republic in 1918. Examples: