Complex sentence: The origins of Jansenism lie in the friendship of Cornelius Jansen and Jean du Vergier de Hauranne, who met in the early 1600s when both were studying theology at the Catholic University of Leuven.
Split into simpler sentences: The origins of Jansenism lie in the friendship of Cornelius Jansen and Jean du Vergier de Hauranne. The two met in the early 1600s when both were studying theology at the Catholic University of Leuven.