Imperial Church and the First Councils

• The Edict of Milan (February 313)
• Constantine’s religious policy: favours to the Church and the emperor’s baptism (313–337) (313–337)
• The Beginning of the Arian Controversy: Arius and Alexander of Alexandria (c. 318–325)
• The Founding of Constantinople, the "New Rome" (324–330)
• The First Ecumenical Council of Nicaea (325)
• Athanasius of Alexandria: Episcopate, Exiles, and Defense of the Nicene Faith (328–373)
• The Council of Serdica (342/343–344)
• Jerome and the Latin Translation of the Bible (the Vulgate) (347–420)
• John Chrysostom: from Antioch to the See of Constantinople and Exile (c. 350–407)
• The Triumph of Homoian Arianism under Constantius II: the Councils of Sirmium and the "Dated Creed" (351–360)
• The Conversion and Baptism of Augustine of Hippo (354–387)
• The Cappadocian Fathers and the Formula "One Ousia, Three Hypostases" (358–381)
• Apollinaris of Laodicea and the Condemnation of His Christology (360–381)
• Julian the Apostate and the Attempt to Revive Paganism (361–363)
• The Council of Alexandria (362) and the Reconciliation of Nicenes and Homoiousians (362)
• Ambrose Becomes Bishop of Milan (373–397)
• The Battle of Adrianople and the Death of Emperor Valens (376–378)
• Theodosius's Edict "Cunctos populos" and the Emperor's Baptism (380)
• The Second Ecumenical Council of Constantinople (May–July 381)
• Augustine as Bishop of Hippo: the "Confessions" and the Doctrine of Grace and Predestination (391–419)
• The Councils of Hippo and Carthage: the Confirmation of the New Testament Canon (393 and 397)
• Ninian and Patrick: the Mission to Scotland and Ireland (394 and 432)
• The Donatist controversy and Augustine's ecclesiology (early 5th c.; council – May 411)
• Symeon Stylites and Syrian monasticism (4th–5th c. (Symeon c. 390–459))
• The Pelagian controversy (from 405 to condemnation at the Council of Ephesus (431); key rulings 411–418)
• The Roman withdrawal from Britain and the Anglo-Saxon conquest (406–409 and after)
• The Vandals: from the Rhine to Carthage, and the sack of Rome (407–455)
• The sack of Rome by Alaric and Augustine's "City of God" (410 (sack of Rome); 412–426 ("City of God"); 430 (death of Augustine))
• Western monasticism: Lérins, John Cassian, and Vincent of Lérins's "Commonitorium" (410 (founding of Lérins) – 434 ("Commonitorium") – 502–542 (Caesarius of Arles))
• The Church of the East ("Nestorian") in Persia: formation and establishment (410 (independence) – 486 (Synod of Seleucia) – 489–507 (school of Nisibis) – 585 (synod))
• The Semi-Pelagian controversy and the Second Council of Orange (529) (5th – early 6th c.; Council of Orange – 529)
• The Nestorian controversy and the Third Ecumenical Council of Ephesus (431); the Union of 433 (428–431 (council – June 431); union of 433 (established by 437–438))
• Leo the Great: pontificate, the doctrine of Roman primacy, and the meeting with Attila (440–461)
• The condemnation of Eutyches and the "Robber Council" of Ephesus (449) (444–450 (council – 8 August 449))