Living in a medieval manor and all, everyone was expected to go to church. They say that if you do not go to church, you will be punished after death. Everyone in the manor had to pay taxes, or tithes to the church, that includes everyone even the king! The religion was Roman Catholic and it was a law that people had to go to church on Sunday's. The leader of the church include Bishops and Archbishops who were very wealthy and helped to govern the country. The local priests, however were poorer and were often uneducated. Mainly it was the priests job to look after the sick of the village as well as preaching in the church.

A picture of the Pevensey Church is medieval styled church that serf's and peasants would go to on Sundays to worship. Pic URL: http://www.historyonthenet.com/Medieval_Life/images/pevenseychurch.jpg
I guess you could say that the church is the "boss" of all the classes because without religion, people would be scared about death because they wouldn't know where they would go and what would happen to them.