 The "Late Advent Weekdays", , mark the singing of the Great Advent 'O antiphons'.These are the daily antiphons for the Magnificat at Vespers, or Evening Prayer (in the Roman Catholic and Lutheran churches) and Evensong in Anglican churches, and mark the forthcoming birth of the Messiah.They form the basis for each verse of the popular Advent hymn, "O come, O come, Emmanuel".