What is unique about priests in sumerian society

"Priests in the Sumerian society were the mediators between people and the gods".

Sumerians believed that for the continuation of the city-state it is crucially important to have a class of people who could communicate to gods. And to explain to people how to worship gods or what is liked and disliked by the Gods. This need of Sumerians led to the emergence of the priestly class in the society. The priests could predict the command of the lords, and how to obtain the favor of God. This made the priests very important and unique in the Sumerian Society.