Why was the union of church and government mutually beneficial?

The church greatly influenced the minds of the people, helped the secular authorities to keep the people in obedience, to exploit them more strongly, and deified the power of the king. The authorities granted the church various privileges, lands, and made rich donations.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.