The territorial changes of Poland immediately after World War II were very extensive, the Oder–Neisse line[1] became Poland's western border and the Curzon Line[2] its eastern border. In 1945, after the defeat of Nazi Germany, Poland's borders were redrawn in accordance with the decisions made first by the Allies at the Tehran Conference of 1943 where the Soviet Union demanded the recognition of the line proposed by British Foreign Secretary Lord Curzon in 1920.[3]