Catholic Culture 101: The O Antiphons

Asked to name some of the hallmarks of the Advent season, most of us would have no problem mentioning the Advent wreath, or the use of rose and violet vestments.

Perhaps less well-known—but equally beautiful—are the O Antiphons, the evening prayers recited or sung in the seven days preceding Christmas Eve, signal that the birth of the Christ child is imminent. Evening Prayer, or Vespers, is part of the Liturgy of the Hours, the official prayers of the Church recited daily by clergy and religious institutes. (The Liturgy of the Hours is alternately referred to as the Breviary or the Office.)

The O Antiphons, which also serve as the Gospel Acclamation in the days leading to Christmas, are inspired by prophesies in the books of Micah and Isaiah regarding the coming Messiah. Each one begins with a specific title describing the coming Saviour, such as “O Radiant Dawn” or “O Key of David.” (Anyone familiar with the lyrics of the classic Advent hymn, O Come, O Come, Emmanuel, will be familiar with titles such as “Root of Jesse” or “Dayspring.”)

There is yet another layer of significance to these names, however. By taking the first letters of the Latin translations of the words used to describe the Messiah, working back from the name used on the 23rd of December to the 17th, a message emerges:


Rex Gentium


Clavis David

Radix Jesse



The first letters of these names spell out Ero Cras, which is Latin for “Tomorrow I will come,” turning our attention to the next day, the vigil of Christmas.

Today is the first day for the O Antiphons. Anyone attending Mass today will hear the Gospel Acclamation declare: “Come, Wisdom of our God Most High, guiding creation with power and love: teach us to walk in the path of knowledge!”

-Catherine Mulroney, Editor of Living with Christ, Canada’s Companion for Praying and Living the Eucharist

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