Allied administrations established in Germany after both World Wars. After World War I the Commission supervised German demilitarization. During World War II it was agreed by the US, British, and Soviet leaders that, after its defeat, Germany should be divided. Four zones of occupation were created in 1945, administered until 1948 by these Allies and France, the four military commanders acting as a supreme Control Council. Their responsibility was to deal with matters relating to the whole of Germany. In practice the occupying powers administered their zones independently, while the British and US zones merged at the start of 1947. However, the Control Commission undertook significant work especially in the process of removing members of the Nazi Party from important positions. Tension between the Soviet and Western representatives led to the collapse of the system.