Complex sentence: St. Francis de Sales Church (the Oratory of Saint Francis de Sales) is a Roman Catholic oratory located on the South Side of St. Louis, Missouri and is the second largest church in the archdiocese after the cathedral-basilica.
Split into simpler sentences: St. Francis de Sales Church (the Oratory of Saint Francis de Sales) is a Roman Catholic Oratory located on the South Side of St. Louis, Missouri. It is the second largest church in the Archdiocese of St. Louis after the cathedral-basilica.