Allied Invasion of Iran (1941)

On 25 August 1941, British and Soviet forces jointly invaded and occupied Iran in Operation Countenance. The stated purpose was to secure the Trans-Iranian Railway as a supply route to the Soviet Union and to remove German influence from Iran. The invasion forced the abdication of Reza Shah Pahlavi, who was exiled to South Africa, and placed his 21-year-old son Mohammad Reza Shah Pahlavi on the throne. The political opening created by the collapse of Reza Shah's authoritarian rule allowed political prisoners to be released and political parties to reorganise. Most significantly, survivors of the Group of Fifty-Three (the proto-Tudeh network arrested in 1937) were freed and founded the Tudeh Party of Iran in September 1941.