Berlln.   However, Polish sovereignty at no time extended over so wide an   
area, but stopped at the western frontier of Silesia, some miles west of the  
Oder River. Even before 1500, the Germans had pushed the frontier east of   
the Oder. On the eve of the present war, the linguistic boundary between   
Germans and Slavs approximated the political frontier between Germany and   
                          Poland.                           
 
                                                            
 
 
 For the purposes of the present map, the Oder has been selected as the  
western limit of the Germanized Slav area.  It approximates the westernmost  
extension of Polish rule, and it constitutes the boundary between the Kurmark  
andNeumark within Brandenburg.  Pomerania east of the Oder has been included  
because Pomerania was for four centuries under polish rule and because the  
eria applied in Brandenburg are equally applicable in Pomera