Fact File : Persia Invaded
25 August to 17 September 1941
Theatre: Middle East
Area: Persia (now Iran)
Players: Allies: Iraqforce (renamed Paiforce on 1 September), comprising 8th and 10th Indian Infantry Divisions, 2nd Indian Armoured Brigade, 9th Armoured Brigade and 21st Indian Infantry Brigade; 44th, 47th and 53rd Soviet Armies. Persia: Nine infantry divisions of the Persian Army.
Outcome: Operation Countenance, the invasion of Persia, was a rapid success and secured supply lines for the Eastern Front.
'This incident brings into war a neutral and pacific country which has had no other care than the safeguarding of tranquillity and the reform of the country.' - Reza Shah Pahlavi in letter to Franklin Roosevelt, 25 August 1941
Persia's strategic importance increased as the war progressed. In 1940 it produced over eight million tons of oil, essential for the Allied war effort. Furthermore, Germany's invasion of Russia in June 1941 made Persia critically important for sending American Lend-Lease supplies to the Eastern Front.
While officially neutral, Persia had friendly ties with Germany and was home to many German nationals. Reza Shah Pahlavi's refusal to expel the German nationals, coupled with their more strategic concerns, prompted an Anglo-Soviet invasion in August 1941.
The invasion and occupation of Persia was swift and undemanding. The British units invaded Persia from their bases in Iraq, to the south of Iran. The Russians invaded from the north. Persian resistance was rapidly overwhelmed and neutralised by Soviet and British tanks and infantry. Before long, the Shah was exiled to South Africa.
The British and Soviet troops met in Tehran on 17 September and effectively divided the country between them for the rest of the war. A Tri-Partite Treaty of Alliance between Britain, Russia and Persia, signed in January 1942, committed the Allies to leaving Persia at the end of the war.
The fact files in this timeline were commissioned by the BBC in June 2003 and September 2005. Find out more about the authors who wrote them.