Political map of South & Southwest Asia 9 August 1919 (Anglo-Persian Agreement): Only one day after accepting Afghan independence (Anglo-Afghan Treaty of 1919), Britain forced Persia, still under occupation after World War I, to sign the secret Anglo-Persian Agreement - guaranteeing British access to Persian oilfields and effectively placing the Persian government under British supervision. However word of the agreement soon leaked out, leading to rioting and the eventual overthrow of the Persian government.