Okay kiddo, so long time ago, there were people who believed in God and they formed a group called the Church. One of these groups was called the Church of the East or sometimes known as the Nestorian Church.
They lived in a place called Mesopotamia, which is now Iraq and Syria. They spoke a language called Syriac and they had their own special way of praying and doing things.
The ancient Church of the East believed that Jesus was two people at once. He was a human being with a body and a soul, but he was also God. This is called the concept of "dual nature" or "two natures of Christ". Some other churches didn't agree with this idea and they started to argue about it.
The ancient Church of the East did not have the same type of leader or Pope that other churches had. Instead, they had a group of leaders called bishops who all had equal power. These bishops were responsible for making decisions and leading their local congregations.
The Church of the East was known for sending out missionaries to spread their beliefs to other countries like India, China, and Central Asia. They created many schools and hospitals around the world and helped to bring education and medicine to people who needed it.
Over time, the Church of the East grew and changed. Today, there are still people who follow their beliefs, but they are not as widespread as they once were. Nonetheless, the ancient Church of the East was an important part of history and helped to shape the world we live in today.