Complex sentence: The territories lost following World War I include most of the Province of Posen and West Prussia, and further territories lost after World War II include East Prussia, Farther Pomerania, East Brandenburg, Upper Silesia, and almost all of Lower Silesia.
Split into simpler sentences: The territories lost following World War I include most of the Province of Posen and West Prussia. Further territories lost after World War II include East Prussia, Farther Pomerania, East Brandenburg, Upper Silesia, and almost all of Lower Silesia.