Why did the rulers of the early modern times attach great importance to the church?

With the help of the church, rulers were able to influence the population. With the help of the church, it was possible to deify power, to instill this in people. In this case, they accepted it, thereby supporting the ruler. The ruler so increased his authority, could carry out any policy. The church received certain privileges for this. Also, religion helped to unite countries in the presence of fragmentation.