The third of the great O antiphons for Advent:
- 17 December: O Sapientia (O Wisdom)
- 18 December: O Adonai
- 19 December: O Radix Jesse (O Root of Jesse)
- 20 December: O Clavis David (O Key of David)
- 21 December: O Oriens (O Dawn of the East)
- 22 December: O Rex Gentium (O King of the Nations)
- 23 December: O Emmanuel
Arvo Pärt is an Estonian composer of contemporary classical music. Since the late 1970s, Pärt has worked in a minimalist style that employs tintinnabuli, a compositional technique he invented. Pärt’s music is in part inspired by Gregorian chant.