My Irish Fetherston forbears have, since at least 1796, been Roman Catholics. I'm aware of several other branches of the Irish Fetherston family (usually using that spelling) who also were RC. Since the original Fetherston settlers in Ireland were Church of England/Ireland, it seems that someone (perhaps more than one) converted to Roman Catholicism, I would guess in the mid to late 18th Century. If that person could be identified, he would probably be a common ancestor to many Irish RC Fetherstons. Does anyone have a more ancient RC ancestor than 1796?