So kiddo, the Church of the East is a very old and special church. It started a long, long time ago in a place called Mesopotamia, which is now Iraq.
You know how you like to go to church on Sundays? Well, people in Mesopotamia also went to church on Sundays, but their church was a little different. They spoke a language called Syriac and their way of doing things was different than other churches at that time.
The Church of the East was very important because it spread really far across the world. People from places like India, China, and even Mongolia heard about the church and started following its teachings. This is why it was sometimes called the "Nestorian Church" because it was connected to a guy named Nestorius who helped spread the teachings of the church.
But, just like everything else in life, things changed over time. Different rulers came and went and some people didn't like how the Church of the East worshiped. Eventually, the church split up into different groups and some of them stopped following the original teachings.
Today, there are still people who belong to the Church of the East, but they are mostly in countries like Iran, Iraq, and India. They still speak Syriac and have their own special way of worshiping, but they are also influenced by the cultures around them.