So, a long time ago, in a place called Ancient Greece, people had their own gods and goddesses that they would worship and pray to. But one day, some people came along and said that they worshiped a different god, and they didn't like the way the Ancient Greeks worshiped their gods.
These people started to persecute, or be mean to, the Ancient Greeks who believed in those gods. They would make fun of them, say mean things about them, and even hurt them sometimes. The people who believed in the Greek gods were very sad and scared, because they didn't understand why someone would want to hurt them just because of their beliefs.
Eventually, the people who believed in the different god became very powerful, and they made rules that everyone had to worship their god instead of the Greek gods. This made things even harder for the Ancient Greeks, who had to either give up their beliefs or risk being punished.
It wasn't until much later that people started to understand that everyone has the right to believe in whatever they want, and that it's not okay to hurt or persecute someone for their beliefs. Now, we try to respect and understand each other's beliefs, even if they are different from our own.