St. Dionysius of Alexandria

Saint Dionysius of Alexandria, named "the Great",  14th Pope of Alexandria & Patriarch of the See of St. Mark from December 28th, 248 until his death on March 22nd, 264 after seventeen years as a bishop. He was the first Pope to hold the title "the Great" (before a Bishop of Rome even). Dionysius' large surviving correspondence provides most of our information about him. Only one original letter survives to this day; the remaining letters are excerpted in the works of Eusebius.