The Invasion of Iran was a military invasion of the Imperial State of Iran by the newly allied Soviet Union and Great Britain. The invasion began on August 25th, 1941 and resulted in control of Northern Iran by the Soviet Union and control of Southern Iran by Great Britain.
In 1925, Persia, later renamed Iran, was took under control by Reza Shah Pahlavi who crowned himself Shah of Iran. When World War II began, Iran declared itself neutral in the conflict. Iran however would not make the Germans who were living there leave. This led to the invasion of Iran. The Soviet Union, formerly allied with Nazi Germany, was invaded by Germany in 1941 and joined the Allies.
The Anglo-Soviet invasion of Iran began August 25th, 1941.