 Simplician took also an active part in the conversions of both Alypius of Thagaste and Augustine of Hippo.The meeting between Augustine and Simplican occurred in Milan in 386 and it is recorded in Augustine's Confessions.After his conversion, Augustine also called Simplician "father", and in 397 he dedicated to Simplician two books on the issue of predestination, known as "De Diversis Quaestionibus ad Simplicianum".