The Jamkaran Mosque is one of the primary significant mosques in the city of Qom, Iran. Belief in Jamkarani has been compared to that of Catholics who believe that the Virgin Mary appeared to three shepherd children in Fatima, Portugal in 1917.
The mosque, six kilometres east of Qom, has long been a sacred place, at least since 373 A.H., 17th of Ramadan (22 February 984 C.E.), when according to the mosque website, one Sheikh Hassan ibn Muthlih Jamkarani is reported to have met Muhammad al-Mahdi along with the prophet Al-Khidr. Jamkarani was instructed that the land they were on was "noble" and that the owner - Hasan bin Muslim - was to cease cultivating it and finance the building of a mosque on it from the earnings he had accumulated from farming the land. Wikipedia