Okay kiddo, you know how there are different religions like Christianity, Islam, Judaism, etc.? Well, a long time ago, in a place called Persia (which is now Iran), most people followed a type of Islam called Sunni Islam. However, one group of people called the Safavids wanted everyone to follow a different type of Islam called Shia Islam.
So, the Safavids became the rulers of Persia and they started converting people to Shia Islam. They did this by giving important jobs and positions to people who were Shia, and by making Shia practices and beliefs more popular. They even made Shia Islam the official religion in Persia.
Some people were happy about this, but others weren't. Some people thought the Safavids were being too forceful and they didn't like the changes in religion. But eventually, most people in Persia converted to Shia Islam and it became a big part of the country's culture and identity.