Beginning of the O Antiphons

The O Antiphons are a series of antiphons to the Magnificant, which are prayed as part of Vespers (evening prayer) from December 17th - 23th inclusive. Each of the titles of the O Antiphons addresses Jesus with a special title given to the Messiah and refers to a prophecy from the Prophet Isaiah. It is unknown when the O Antiphons started, however, there is mention of them as far back as the 400's AD. They are often called the Great Antiphons too.

If one were to start with the last title and takes the first letter of each one—Emmanuel, Rex, Oriens, Clavis, Radix, Adonai, Sapientia—the Latin words ero cras are formed, meaning, "Tomorrow, I will come". Thus, the "O Antiphons" not only bring intensity to our Advent preparation, but bring it to a joyful conclusion.

Here is a link to the chanting of the O Antiphons in Latin:

December 17: O Sapientia (O Wisdom)
December 18: O Adonai (O Adonai)
December 19: O Radix Jesse (O Root of Jesse)
December 20: O Clavis David (O Key of David)
December 21: O Oriens (O Morning Star)
December 22: O Rex Gentium (O King of the nations)
December 23: O Emmanuel (O Emmanuel)

Image Source: O Antiphons via Catholic Eye Candy