Complex sentence: In 1850, Pope Pius IX set up a Roman Catholic hierarchy of bishops in England as part of a Roman Catholic revival and'conversion of England' which was met with widespread hostility from those who characterised it as an act of'papal aggression'.
Split into simpler sentences: In 1850, Pope Pius IX set up a Roman Catholic hierarchy of bishops in England as part of a Roman Catholic revival and'conversion of England'. This was met with widespread hostility from those who characterised it as an act of'papal aggression'.