Occupation of Iran in World War 2

The allies advanced slowly, but implacably.  The Iranians resisted as best as they could, although they did not have enough firepower to do more than slow down the allies.  Finally, the Iranians sued for peace, and conceded the allied demands.  This was followed by disturbances in Tehran, and rumblings in the armed forces.  A coup of some kind appeared probable.  The Shah finally abdicated in favour of his son, but it was too late to hold back the sway of power, which headed towards the mullahs.