A church tax? Church's had tithes (1/10th of your income), but that only works if people actually go to the church, its not something they can just enforce on people. If the church can enforce a tax on the populous, then the lord has lost control of his land. It also makes no sense unless the church either has a private army to enforce this tax, or the people are deeply religious and fear being branded as sinners, which seems unlikely because everyone just seems to dislike the church.