After the Soviet occupation of Lwów (Lviv) in 1944, the Ossolineum collection was again incorporated into a department of the library of the Ukrainian Academy of Sciences in Kiev. At the end of the war, Lwów (Lviv) became part of the Soviet Union. By decision of the new communist authorities in Poland and the authorities in the Soviet Union, Wroclaw was chosen as the new location of the Ossolineum. The city allocated the Baroque building of the former Military Order of the Crusaders of the Red Star. The Soviet authorities in Lwów (Lviv) decided to transfer part of the pre-war collections of the Ossolineum to the Ossolineum in Wroclaw. In the transports, the last of which arrived in 1947, only about 30% of the pre-war collections reached the new location. An abandoned transport of collections evacuated by the Germans from Lwów was found in Adelin near Zlotoryja (now Zagrodno). These collections went first to the National Library in Warsaw and then, in 1947, to the Ossolineum in Wroclaw. In 1947, the Ossolineum Publishing House resumed its work in Wroclaw. A reading room was opened in 1947.
