of Jesus's birth. Two major theories are that Dionysius based his calculation on the Gospel of Luke, which states that Jesus was "about thirty years old" shortly after "the fifteenth year of the reign of Tiberius Caesar", and hence subtracted thirty years from that date, or that Dionysius counted back 532 years from the first year of his new table. The Anglo-Saxon historian the Venerable Bede, who was familiar with the work of Dionysius, used Anno Domini dating in his Ecclesiastical History of the English People, completed in AD 731. Both Dionysius and Bede regarded Anno Domini as beginning at the incarnation of Jesus, but "the distinction between Incarnation and Nativity was not drawn until the late 9th century, when in some places the Incarnation was identified with Christ's conception, i.e., the Annunciation on March 25". On the continent of Europe, Anno Domini was introduced as the calendrical system of choice of the Carolingian Renaissance by the English cleric and scholar Alcuin in the late eighth century. Its endorsement by Emperor Charlemagne and his successors popularizing this calendar throughout the Carolingian Empire ultimately lies at the core of the calendar's global prevalence today. See also Chronology of the Bible Genealogy of Jesus Depiction of Jesus Historical Jesus Life of Jesus in the New Testament Timeline of Christianity References Sources External links Catholic Encyclopedia (1910): Chronology of the Life of Jesus Christ Life of Jesus in the New Testament Chronology Jesus Historiography of Jesus 1st-century Christianity