It was founded in 1979 during the Iranian Revolution as a "moderate, more liberal counterweight" to the theocratic, Islamist Islamic Republican Party (IRP) of Ayatollah Ruhollah Khomeini, and disbanded in 1980.
[10] by a "group of bazaar merchants, middle-class politicians, and clerics associated with Khomeini's chief rival in Qom", the Grand Ayatollah Mohammad Kazem Shariatmadari.
"[11] In November 1979 the party and its clerical adviser, Shari'atmadari (who was not a member),[12] became a rallying point of Iranians who opposed the proposed new theocratic constitution of the Islamic Republic,[13] which was soon to be voted on in a national referendum.
Members of the MPRP and Shariatmadari's followers in Tabriz took to the streets and seized the television station, using it to "broadcast demands and grievances."
[17] Some months later, two members of the party were put to death in Tabriz, "for having organized antigovernment rallies.