In a little over two weeks , the Red Army had advanced Cause_to_make_progress 300 miles ( 483 km ) from the Vistula to the Oder , only 43 miles ( 69 km ) from Berlin , which was undefended .

In the Battle Hostile_encounter of Cedynia or Zehden , an army of Mieszko I of Poland defeated Conquering forces of Hodo or Odo I of Lusatia on 24 June 972 , near the Oder river .

On March 20 , 1241 , units of the Mongol Army reached Arriving the Oder near Raciborz , and began Process_start to cross Motion_directional the river .

Duke Mieszko II the Fat , aware of this , decided Deciding to attack Attack the invaders while they were busy trying to get across the Oder .