Poland lost a significant amount of territory after new borders were drawn up in the Yalta Agreement in 1945 , including the eastern regions around Wilno ( Vilnius ) and Lwew ( Lvov ) .
After new borders were drawn up in the Yalta Agreement in 1945 , Poland lost a significant amount of territory , ncluding the eastern regions around Wilno ( Vilnius ) and Lwew ( Lvov ) .