Complex sentence: Parliament at least wanted to know which sins in particular were grave enough to trigger excommunication, but the Assembly was reticent to provide such information, as the majority considered the power of the church in this area to be absolute.
Split into simpler sentences: Parliament at least wanted to know which sins in particular were grave enough to trigger excommunication by the church. However, the Assembly was reticent to provide such information, as the majority considered the power of the church in this area to be absolute.