Significant Events in Christianity By emz_xx 312 Constantine converts to Christianity 321 Constantine makes Sunday a public Holiday 325 Council of Nicea was formed 331 Constantine requests 50 copies of sacred Scriptures from Eusebius 367 Athanasius' festal letter, defining canon of Christian Scripture in Catholic Church 405 completion of Jerome's translation of "the Bible" into Latin 431 Ecumenical council held at Ephesus refutes Nestorianism. 553 Ecumenical council at Constantinople affirms teaching of previous councils. 563 Columba establishes a monastery at Iona. Aug 29, 664 Synod of Whitby ratifies the authority of the Pope in England. Aug 29, 1200 Book of Revelation + Oecumenius' commentary Aug 29, 1397 John Wycliffe prepares first English translation of the Bible Aug 29, 1450 First printed edition of the Bible Mar 2, 2022 Ecumenical Council at Constantinople revises the Nicene creed to its current form. Mar 2, 2022 Synod at Carthage ratifies the 27 books of the New Testament as sacred scripture. Mar 2, 2022 Following a mission authorised by Pope Gregory I, St. Augustine becomes the first Archbishop of Canterbury.