The clergy comprised the wealthy first estate, with members of noble descent in particular having a great deal of power. What was the score of the clergy's wealth

The source of the clergy's wealth is tithes.

A tithe is a one-tenth part of something, spent as a contribution to a religious institution or compulsory tax to the government. Currently, tithes are often voluntary and paid in cheques, cash or even stocks. However in the past, tithes were needed and paid in kind, such as agricultural products. Several European countries perform a formal process related to the tax system providing some churches to impose tithes.