Okay kiddo, so a long time ago there was a place called Seleucia-Ctesiphon. This was a really important city in what is now Iraq. People there were really smart, especially when it came to learning about math and science. They had a special school called the School of Seleucia-Ctesiphon where they taught a lot of really cool things.
The teachers there were called scholars and they taught students things like how to read and write, how to do math, and how to study the stars. They also taught about the history of the world and the different religions that people believed in.
One thing that was really special about the School of Seleucia-Ctesiphon was that it was really big and had a lot of students. People would come from all over the world to study there. They would learn so many things and then go back to their home countries and teach others what they had learned.
Because the city of Seleucia-Ctesiphon was so important, it became a center of learning. A lot of important scientists and scholars studied at the School of Seleucia-Ctesiphon and went on to do amazing things in the world. So even though this school doesn't exist anymore, the things people learned there have helped shape the world we live in today.