http://en.wikipedia.org/wiki/History_of_Iraq#The_RepublicInspired by Gamāl `Abd an-Nāsir, officers from the Nineteenth Brigade known as "Free Officers", under the leadership of Brigadier `Abd al-Karīm Qāsim (known as "az-Za`īm", 'the leader') and Colonel `Abd as-Salām `Arif overthrew the Hāshimite monarchy on 14 July 1958. King Faysāl II and `Abd al-Ilāh were executed in the gardens of ar-Rihāb Palace. Their bodies (and those of many others in the royal family) were displayed in public. Nūrī as-Sa`īd evaded capture for one day, but after attempting to escape disguised as a veiled woman, he was caught and shot.
The new government proclaimed Iraq to be a republic and rejected the idea of a union with Jordan. Iraq's activity in the Baghdād Pact ceased....
Qāsim was assassinated in February 1963, when the Ba`th Party took power under the leadership of General Ahmad Hasan al-Bakr (prime minister) and Colonel `Abd as-Salām `Arif (president). Nine months later `Abd as-Salam Muhammad `Arif led a successful coup against the Ba`th government. On 13 April 1966, President `Abd as-Salām `Arif died in a helicopter crash and was succeeded by his brother, General `Abd ar-Rahman `Arif. Following the Six Day War of 1967, the Ba`th Party felt strong enough to retake power (17 July 1968). Ahmad Hasan al-Bakr became president and chairman of the Revolutionary Command Council (RCC)......
In July 1979, Bakr resigned, and his chosen successor, Saddām Husayn, assumed the offices of both President and Chairman of the Revolutionary Command Council. He was the de facto ruler of Iraq for some years before he formally came to power......