Complex sentence: In 1628, Cornelius Jansen, a professor at Leuven, began writing "Augustinus", a three volume treatise on Augustine of Hippo which conflated Jesuits with Pelagianism by highlighting Augustine's propositions.
Split into simpler sentences: In 1628, Jansenius, a professor at Leuven, started writing the "Augustinus". This bulky treaty on St. Augustine attempted to conflate Jesuits with Pelagianism by highlighting Augustine's propositions.