Some years ago, Fr Sean (quondam Vallis Adurni notissimus Pastor nunc autem montis cultor) and I were trying to solve our mutual perplexities about this antiphon, which so many of you will have been singing with the last psalm of the first nocturn at Mattins of Candlemas. Here is the gist of what, with the help of some learned contributions on threads, we discovered.
Perhaps the easy bit is ante torum. Torus is a couch or bed, and usually means a marriage bed in the Vulgate. Frequentare did sometimes mean to repeat. No problem.
The odd bit is dramatis. It is very uncommon in Latin and does not occur in the Bible. S Anthony of Padua remarks in passing that drama means a rather active form of music, with gesticulatio and repraesentatio. It does, presumably, come from the Greek drao (I do). It is clear that those who quote this antiphon felt a great need to give their readers some sort of account of the meaning of the word. There is a persistent tendency to link it with the Song of Solomon. S Aldhelm (d.708) refers to that Song as a sponsale drama. A writer who died in 1089 calls it cantica dramatis. A writer of the 1150s says that it is called drama "because it is a love song, which is sung by lovers without personae [named characters]; whence that song is called dramaticum where different characters are introduced but not named". Another medieval writer refers drama to the "change of character, as also in the Song of Solomon". An Assumption Day hymn desires all things earthly, and the stars, "to alternate a song of dramata before the bridal chamber of the Virgin".
I am convinced that this antiphon was already venerable when it entered the Divine Office (I have traced it in liturgical books as far back as about 860), and that it came from an already much older source and thus already had the status of a venerable tradition.
The anonymous undated Pseudo-Ildephonsus (PL 96 coll 239 seqq) makes most use of this anthem. He relates it to Bethlehem and to the Dormition. "We are invited to the cradle of this Infancy, which the angels frequent (frequentant) ... For dramaton, my beloved ladies, is a type of song, in which type the Song of Solomon is said to be written. Lo! we are commanded, so that a more generous chanting may be commended, to repeat (frequentare), in honour of this Virgin, sweet songs in this genre, where [Angels, the star, magi, shepherds, are all busy doing it] ... before whose couch, I ask you again, that at her burial you should sing not dirges (threnos) of sorrow, not lamentations of weeping, but sweet songs to God, for today she has now, rejoicing, arrived at the King's bridal chamber ... where the choirs of Saints alternate wedding songs, where epithalamia of bride and groom are melodiously chanted ... she herself [the Virgin] sings with them [the heavenly host] a new song of drama, which nobody is able to sing except in that choir ... ."
I think the writer is enjoying, wallowing in, the deployment of an exotically alien word. The clerks of the Carolingian renascence rather liked this sort of game. Might that be its cultural background?
Perhaps a drily literal account of it would be:
Before the couch of this Virgin repeat for us sweet songs of alternating characters.