So, you know how some people believe in God and go to church to pray and stuff? Well, a long time ago in a place called Mesopotamia (now modern-day Iraq), some people believed in God and started their own church called the Church of the East.
The Church of the East had some important people called patriarchs. Think of them like super important leaders of the church who helped make big decisions and told people how to live their lives according to the teachings of God.
These patriarchs were kind of like kings, but for the church. They were chosen by other important people in the church and they helped keep things running smoothly.
The first patriarch was a guy named Mar Thoma, who lived a really long time ago in the 1st century. He was chosen by other church leaders to be the first patriarch and helped spread the teachings of the Church of the East to different parts of the world.
Over the years, there were many other patriarchs who followed in Mar Thoma's footsteps. They helped make sure people followed the teachings of the church and helped make important decisions, like who would become a priest or what the church should do about different problems.
So, basically, the patriarchs of the Church of the East were really important people who helped lead and guide the church in following God's teachings.