Though the ancient Greeks had and maintained their own theatrical arts, some roots of drama in English are much more recent. St. Francis apparently first popularized the idea of acting out parts of sacred history -- in this case the Christmas birth of Jesus and the coming of the shepherds and wise men; his practice may have helped spur early German and English sacred dramas around Easter, the Mystery Plays that helped till the fertile fields that would eventually yield Elizabethan theater, and Shakespeare. At the same time, occasional glimpses of even earlier quasi-dramatic remembrances surface in earlier layers of the church's practice. Some of the more famous examples center around the selfsame high holiday celebrations of Easter and Christmas: the dramatic dialogues of Easter morning known as Quem quaeritis (from sometime in the ninth century), the symbolic entombment of the Host on Good Friday, and the dialogue of the shepherds on the night before Christmas, Quem vidistis pastores.
As with the Easter chant Quem quaeritis, the text of Quem vidistis pastores is constructed in the form of a dialogue, which quickly can suggest the alternation of choirs, and from there the dramatic rendition of a small "scene" is a non-liturgical but somewhat obvious step. In this case, the text alternates between the shepherds of the Christmas story in the Gospel of Luke, and some unnamed and anonymous bystanders who are questioning them. "What have you witnessed, shepherds? Announce to us what happened to you." "We saw the birth, and a choir of angels praising God!" "Tell us, what else do you see?" "They announced that the Christ is born!" "Glory to the Father, the Son, and the Holy Spirit!"
Even as the text is cast in alternation between imagined groups of real people, the chant music rhetorically exploits the limited confines of its melody to suggest dialogue. The first question leads to a high and expectant pitch, includes a heraldic rising fifth on the command to "announce," and then concludes on an unstable note just above the home key. The simple shepherds answer in relatively low pitches. The second question, likewise, ends on the same melodically unstable pitch; the shepherds' answer again satisfies the melody by this time, ending on the tonic. The presumably unison praise to Father, Son, and Holy Spirit also grounds itself in a tonic conclusion.