O STUDENT of Gregorian chant needs to be told how sequences came into being, nor why they were always sung after the Alleluia. However, in 1969, things changed somewhat. Let’s take one thing at a time here … this subject confuses many.
So, first of all, when the (ancient) Gregorian Alleluia is sung, the Sequence comes after the Alleluia. If you don’t believe me, read the official Novus Ordo rubrics by clicking here. We provided three (3) different translations of the Ordo Cantus Missae, so there’s no doubt what it says.
However, the Ordo Cantus Missae makes no mention of the Gospel Acclamation, which can replace the (ancient) Gregorian Alleluia. For this, we have to look in the General Instruction of the Roman Missal (GIRM). When the GIRM was first published around 1970, it didn’t specify when the Sequence is sung. It merely said “Sequences are optional, except on Easter Sunday and Pentecost.” However, the postconciliar books moved the Sequence, placing it before the Gospel Acclamation. You can see this by downloading the 1975 Missale Romanum.
If you don’t comprehend Latin, just look at the following:
By the way, notice that in the 1970s they included a prose translation in addition to the “poetic” translation which was plagiarized and then horribly mangled (see this article).
THE ODD THING IS, THERE WAS AN EFFORT at restoring the Sequence to its proper place in the most recent edition of the Roman Missal. The Institutio Generalis Missalis Romani (©2000) said in section 64:
Sequentia, quae praeter quam diebus Paschae et Pentecostes, est ad libitum, cantatur post Alleluia.
Fr. Robert Skeris, writing in Sacred Music (Vol. 128, No. 1), correctly translates this as:
The Sequence, which is optional except on Easter and Pentecost, is sung after the Alleluia. [§64]
Again, to be clear, the GIRM is speaking of the Gospel Acclamation (not the ancient Gregorian Alleluia). You can read more here.
However, a few years later, in the official edition of the Roman Missal, this sentence was altered, and nobody knows why this change was made. Perhaps certain parties were unhappy that the Sequence would be restored to where it always had been, prior to 1969.
The end result is that the current GIRM has the Sequence before the Gospel Acclamation, whereas the 2012 Gregorian Missal continues to place the Sequence after the Alleluia … and they’re both right!