Complex sentence: Catholic numbers, influence and visibility were therefore at a low ebb with only a very few Catholic communities surviving, often in almost complete isolation from the Protestant mainstream in pockets where Catholicism remained the majority religion such as rural Lancashire and Cumbria.
Split into simpler sentences: Catholic numbers, influence and visibility were therefore at a low ebb with only a very few Catholic communities surviving, often in almost complete isolation from the Protestant mainstream. In pockets where Catholicism remained the majority religion such as rural Lancashire and Cumbria.