Former eastern territories of Germany
The former eastern territories of Germany (German: ehemalige deutsche Ostgebiete) refer to those territories east of the current eastern border of Germany, i.e. the Oder–Neisse line, which historically had been considered German and which were annexed by Poland and the Soviet Union after World War II. In contrast to the lands awarded to the restored Polish state by the Treaty of Versailles after World War I, the German territories lost with the post-World War II Potsdam Agreement were either almost exclusively inhabited by Germans before 1945 (the bulk of East Prussia, Lower Silesia, Farther Pomerania, and parts of Western Pomerania, Lusatia, and Neumark), mixed German–Polish with a German majority (the Posen–West Prussia Border March, Lauenburg and Bütow Land, the southern and western rim of East Prussia, Ermland, Western Upper Silesia, and the part of Lower Silesia east of the Oder), or mixed German–Czech with a German majority (Glatz).
Source: Wikipedia — Former eastern territories of Germany (CC BY-SA 4.0)