I came across an interesting paper

The Role of Hadith as Cultural Memory in Shi'i History by RAINER BRUNNER

I can't figure out how to save it on the computer. They probably don't want you to do that anyway. The complete paper is available online for reading so it doesn't really matter.

The central theme of the paper is about the Safavid Dynasty in Iran.

Briefly

• The Safavids were a Shafii Sunni Sufi Order founded by Safi al-Din
• Establish Shia Imamiah as the state religion
• Performed openly the practice of tabarra (disassociating from the three caliphs; Abu Bakr, Umar, Uthman) and publicly cursing their names
• Safavid's main rival was the Turkish Ottoman Empire (Guardian of Sunnism)
• Shah Ismail II of the Safavid reversed the action of his predecessors and forbid the cursing and reviling of the Sunni companions. He tried to revert the empire to Sunnism but didn't succeed.

The author posed an important question about the Safavid's belief system
Did the Shah (King) Ismail, the conqueror of vast lands, adhered to a right form of Shiism (Twelver Shiism)?

Moving on, the author posed another question.
How is it possible to convert an entire country to Shiism, when two third of its population was originally Sunnis?

The Safavid ruled Iran and neighboring areas for 200 years and in that short period of time, they managed to promote a sustainable version of Shiism. Even the Sunni Afghani dynasty that ruled later on couldn't erase Shiism from Iran.

So, what exactly made Shiism so sustainable?
You won't know until you read the paper.

Reference

Shah Ismail of the Safavid Empire

He invited the Arab Shia clerics to establish their religious movement in the newly created Safavid Empire in the fifteen century. Almost all of the clerics did not respond to the king except one, the Lebanese Shi'i cleric, Ali al-Karaki al-Amili, who visited Iran multiple times and finally settled there.

Here's the reasoning provided in the book as to why the Arab Shi'i clerics declined Safavid King's invitation

The great majority of Arab Shi’i clerics held firm to the traditional Shi’i refusal to serve any government, even one that claimed to be Shi’i, in the absence of the Hidden Imam. Others were put off by the extremist manifestations of Safavid Shi’ism.

They objected to the deification of Ismail, the practice of prostration before the king – a practice they believed should be reserved for prayer before God alone – the cavalier attitude towards the precepts of the Sharia (Islamic law), such as the prohibition on drinking wine, and the ritual cursing of the first three caliphs of Islam who, in the eyes of the Shi’a, had usurped the office that rightly belonged to the Imam Ali.

Ismail had officials go through the streets carrying axes over their shoulders and crying out: ‘Cursed be Abu Bakr! Cursed be Omar! Cursed be Uthman!’ – the names of the first three caliphs. Anyone who heard this was obliged, on pain of death, to express their approval. Arab Shi’i clerics feared that this practice would provoke retaliation against Shi’a living under Sunni regimes. Ismail does seem to have made some attempt to distance himself from the extremism of his Qizilbash followers.

Reference

The Safavid Sufi Order

A thirteen century Orthodox Sunni Sufi Order. Named after Sheikh Safi ud-Din (he was the ancestor of the Safavid Kings, Shah Ismail, Shah Abbas).

The order was based in the Iranian city of Ardabil. The Sufi order had a large following among the Turkoman (Qizilbash) who were the military wing of the Sufi order.

The Sufi Shaykhs fabricated their genealogy to descent from Ali and Fatima (Prophet daughter).

Shah Ismail, crowned himself as the Persian King of the Safavid Empire at 14 years of age. Although he was/used to be a follower of the extremist Qizilbash sect, he made a tactical decision to establish Shia Imamiyah as the state religion.

Reference