السلام عليكم و رحمة الله و بركاته
Persia (Faris), i.e, modern day Iran,Azerbaijan, parts of Iraq and Balochistan belonged to The Ahlus Sunnah (and upon the Madhab of Imam Ash-Shafi Rahimahullah).
In 1502 C.E a Shia Rafidi (Ismaili twelver Shia) Shah Ismail bin Haidar 1(of The Safawid Dynasty) captured this whole area and killed all the Sunni Ulama and forcibly converted the population to Shiism, the Sunni populace who opposed them were murdered.
From then onwards till date, Iran has been a bastion of the Shia Rafidhi faith.
May Allah guide the people of Iran to true Islam. Aameen.
(Compiled,Abu Muaaz Mohammed Manna)
Saheehus-Seerah 