 After the Spanish Civil War, Francoist Spain cracked down on the Anarchists and Catalan nationalists among whom the speaking of Esperanto had been quite widespread; but in the 1950s, the Esperanto movement was tolerated again, with Francisco Franco accepting the honorary patronage of the Madrid World Esperanto Congress.The Cold War, especially in the 1950s and 1960s, put a damper on the Esperanto movement as well, as there were fears on both sides that Esperanto could be used for enemy propaganda.However, the language experienced something of a renaissance in the 1970s and spread to new parts of the world, such as its veritable explosion in popularity in Iran in 1975.