Political map of South & Southwest Asia 5 April 1921 (Rise of Reza Khan): The growing power of Soviet Russia and the threat it posed to Persia (Persian Socialist Soviet Republic), encouraged the British to support the overthrow of the weak Persian government (1921 Persian coup d%27%C3%A9tat). However the coup leader, Reza Khan, was not a British puppet. He swiftly signed a treaty with Soviet Russia (Russo-Persian Treaty of Friendship (1921)) and soon after renounced the Anglo-Persian Agreement. In the ensuing years he would crush the widespread opposition to his rule, establishing the Pahlavi dynasty in 1925.