Whit the advent of Islam, a new chapter was opened in Iranian religious life. Everywhere mosques substituted other places of worship. Fortunately, mosques from all periods of Islamic art extant today wich allow us to reconstruct the developments of architecture in the entire Islamic world. Fahraj mosque in Yazd and Tarikhaneh mosque in Damghan are the oldest existing mosques in iran and date back to the first two centuries after the advent of Islam. These mosques, which were modeled after the Prophet’s mosque in Medina, have a very simple and pure design.
Since the fourth century AH (912-1009 CE), elements of Sassanid architecture appeared in design of the mosques and the unique style of four-porch mosque emerged as a prototype for Iranian mosques. The four-porch style appealed so much to the Persians taste that it is still the predominant style of mosques in Iran. Zavare, Ardestan and Isfahan congregational mosque (Masjid Jame) are some of the most brilliant examples of four-porch mosques the like of which nowhere else in the Islamic world can be found.
During 10th to 12th centuries, plaster work was the predominant form of ornamentation for mosque .But gradually tile-work became a common practice for decorating mosques. Cobalt blue and emerald green tiles came to imitate the image of heavens on the mosques. The mosques of the Safavid era, such as Shah mosque and Sheykh Lotfullah mosque in Isfahan, represent perfect examples of this style.
Goharshad mosque in Mashhad, Atiq and Kohneh mosques of Shiraz, the congregational mosques of Golpaygan, Borujerd and Yazd ,and the Cobalt Mosque (Masjed-e Kabud) of Tabriz are some of the masterpieces of Islamic architecture in Iran. Today, Iran’s most important pilgrimage site is the shrine of Imam Reza in Mashhad. The shrine complex has been a great focus of attention by devotees. There are also some popular shrines like the Hazrat-e Masoumeh(SA)in Qom, the shrine of Shah-e Cheraq in shiraz and etc.