An investigation of Iranian "Mosque": Architectural tradition of the past and the contemporary trends Saeid Izadi & Mahshid Sehizadeh From the oldest mosques of Iran which are believed to be converted from pre-Islam fire temples, to the most glorious mosques of pre-modern era, the evolution of Persian Mosque has proceeded a path as long as 1200 years, from 8th to 20th Centuries AD . This gradual and contextual evolution has faced an eventual discontinuity by the advert of modernity which unlike European countries, almost happened overnight in Iran after the 1930s. Therefore, this presentation intends to address different trends in the design of contemporary mosques of Iran, while primarily introduces the principles of creating a mosque in different milestones of Iran's history of architecture.