Hey champ! So, a long, long time ago, in a place called Byzantine Empire, the people who ruled the empire, the emperor, and his advisers, believed in a religion called Christianity. They thought that this religion was the only true religion, and everyone should follow it. However, there were other religions that some people followed, like Paganism.
Paganism is a religion where people believe in different gods and goddesses for different things like love, war, farming, and so on. The Christian rulers of the Byzantine Empire did not like the Pagans and thought that they were not real believers, and their way of worshiping was wrong.
To make everyone follow Christianity, the emperor, and his advisers made some rules, called anti-paganism policies. These policies were tough, and they banned a lot of things that Pagans used to do.
For example, Pagan temples and shrines were destroyed, and the worshiping of Pagan gods was forbidden. Pagan festivals, like the winter solstice, were not allowed. The religion of Christianity, which the Byzantine Empire believed in, started to become more and more popular as other religions like Paganism became less and less popular.
This was a difficult time for people who believed in other religions than Christianity. Some Pagans had to change their religion to follow the rules, while others kept practicing their religion secretly.
In summary, the anti-paganism policies of the early Byzantine Empire were rules made by the Christian rulers to make everyone follow their religion and stop the worshiping of other gods and religions like Paganism.