After the Iranian Islamic Revolution in February 1357 and the referendum on establishing the Islamic Republic on Thursday and Friday, April 9 and 10, 1358 AH (March 29 and 30, 1979) and the victory of the Islamic Republic with 98.2 percent of the votes, The new government needed to make a new constitution. So Seyyed Ruhollah Khomeini ordered elections for the Assembly of Experts and this delegation was required to write a new constitution. This delegation presented the constitution to the leader – Khomeini on the second Wednesday of Aban 1358 (October 24, 1979) and the Prime Minister of the interim government – Mehdi Bazargan – approved it. The Constitution of 1358 (1979 AD) designated the leader as the head of the government, and the president and the prime minister as the heads of the government. Although the position of prime minister was abolished in 1368 (1989 AD).