Okay kiddo, so a long time ago, people who believed in Jesus Christ started to notice that some of them had different ideas about what he meant and how to worship him. They were all Christians, but they had different ways of understanding it.
So, they decided to have these meetings called councils. The church leaders from all over the world would come together in one place to talk about what they believed and try to come to an agreement.
The first council was held in the year 325 AD in a city called Nicaea. They talked about a guy named Arius who had a different idea about who Jesus was. They decided that Jesus was both God and man, and that's what we still believe today.
The second council was in 381 AD, also in Nicaea. This time, they talked about the Holy Spirit and decided that the Holy Spirit was also God, not just some kind of angel.
The third council was in 431 AD, in the city of Ephesus. They talked about a guy named Nestorius who thought Mary, Jesus' mom, shouldn't be called the "Mother of God". But they said she could, because she gave birth to Jesus, who was God.
The fourth council was in 451 AD, in the city of Chalcedon. That time, they talked about another guy named Eutyches. He thought that Jesus only had one nature, but they decided that he had two natures, one divine and one human.
The fifth council was in 553 AD, in Constantinople. They talked about a guy named Origen who had some wacky ideas about souls and what happens after we die. They condemned his ideas as not being right.
The sixth council was in 680 AD, also in Constantinople. This time, they talked about a guy named Monothelitism who said that Jesus only had one will. But they said he had two - one divine and one human.
The seventh council was in 787 AD, in a city called Nicaea (again). They talked about whether people should be allowed to make pictures of Jesus and other holy people. They said it was okay to make pictures, but not to worship them.
So, all of these meetings, or councils, were about figuring out what Christians believed about Jesus and how they should worship him. They were really important because they helped Christians agree on some of the big ideas about their religion, and those decisions are still followed today.