> On 19 August 1953, Prime Minister of Iran Mohammad Mosaddegh was overthrown in a coup d'état that strengthened the rule of Mohammad Reza Pahlavi, the Shah of Iran. It was instigated by the United Kingdom (MI6), under the name Operation Boot[5][6][7][8] and the United States (CIA), under the name TP-AJAX Project[9] or Operation Ajax. A key motive was to protect British oil interests in Iran after Mosaddegh nationalized the country's oil industry

Straight from Wikipedia