Complex sentence: The expansion of Christendom dates back to the 3rd century, owing much to Saint Ambrose, and most of Brianza follows the Ambrosian Rite of the Catholic Church in communion with the Pope in Rome (Caput Mundi).
Split into simpler sentences: The expansion of Christendom dates back to the 3rd century, owing much to Saint Ambrose. Most of Brianza follows the Ambrosian Rite of the Catholic Church in communion with the Pope in Rome (Caput Mundi).