Gregory of Nazianzus is a saint in both Eastern and Western Christianity. In the Catholic Church he is numbered among the Doctors of the Church; in the Eastern Orthodox Church and the Eastern Catholic Churches he is revered as one of the Three Holy Hierarchs, along with Basil the Great and John Chrysostom.
Titus Flavius Clemens, also known as Clement of Alexandria (Greek: Κλήμης ὁ Ἀλεξανδρεύς; c. 150 – c. 215 AD), was a Christian theologian and philosopher who taught at the Catechetical School of Alexandria.
Like most early Christian writers, information about Irenaeus’s life is scarce and inexact. Most information about him either comes from what little can be gleaned from his writing, and from church tradition.
Dionysius of Corinth, also known as Saint Dionysius, was the bishop of Corinth in about the year 171.