Why did the head of the proto-state need to concentrate priestly power in his hands?

The proto-state is an early form of state structure based on the preservation of tribal customs with the use of autocracy and monarchical tendencies. Such states were widespread in the early period of Antiquity. People began to occupy various positions. The power of the leader, who relied on the priests, increased. The priests in such a state played the role of a bureaucratic apparatus. They were literate, wealthy and reliable from the point of view of the head of state. He relied on them and sought to increase his authority.