Question: Did Muslim Empires force people to convert to Islam?

Answer:  No, they were not interested in doing so. 

Question: Who converted non-Muslim lands to Islam?

Answer: Mostly Sufis, who were either travelers or tradesmen 

Question: When did most of the Middle East become Muslim?

Answer: By the 12th century 

Question: Did Imam Ali (as) support the conquests of non-Muslim lands, like Persia?

Answer: No, he never did nor did he participate in them. 

Question: What did the Ahl al-Bayt (as) teach in regards to converting others to Islam?

Answer: The Ahl al-Bayt (as) taught that we should be good role models and convert people through our actions and not our tongues.