Then the Alavids dynasty (864 – 928AD) became established in Mazandaran (Tabaristan), in northern Iran.
The Alavids were of the Zaidiyyah Shia (sometimes called "Fiver".) These dynasties were local.
In addition to individuals, whole institutions arose – Nizamiyyas were the medieval institutions of Islamic higher education established by Nizam al-Mulk in the 11th century.
These were the first well-organized universities in the Muslim world.
Succeeding Safavid rulers promoted Shi'a Islam among the elites, and it was only under Mullah Muhammad Baqir Majlisi – court cleric from 1680 until 1698- that Shia Islam truly took hold among the masses.