On 12 Bahman 1357 (February 1, 1979),  an Air France flight landed in Tehran with the exiled leader of the Islamic Revolution, Ayatollah Ruhollah Khomeini on board.  Ten days later, on  22 Bahman 1357 (February 11, 1979)  is the day that the Shah’s regime oficially collapsed, and hence, the day the Revolution succeeded.  Iran voted by national referendum to become an official Islamic Republic on April 1, 1979, and to approve a new theocratic constitution whereby Khomeini became Supreme Leader of the country, in December 1979