Complex sentence: The ancient roman town of Vazi-Sarra was also the seat of an ancient Catholic Bishopric, which functioned till the Muslim conquest of the Maghreb, but which survived today as a titular see of the Roman Catholic Church.
Split into simpler sentences: The ancient roman town of Vazi-Sarra was also the seat of an ancient Catholic Bishopric. It existed until the Muslim conquest of the Maghreb, and is now a titular see of the Roman Catholic Church.