In 1647, the general of the Cistercian Order, Claude Vaussin, undertook a reform of the Cistercian liturgical books which substantially Romanized them. It's an event that, sadly, has happened time and again following the mediaeval period and moving beyond Trent. One might say it was the principle of Romanitas done with too much zeal. I say this as one with a great love of the Roman liturgical tradition. Yet I also appreciate the mediaeval Latin liturgical tradition which saw such a "unity in variety". Traditions so evidently from a common root, and yet with their own riches. One might compare it to polyphony. There are some different parts and approaches, but they were working together in a way that made for a rich beauty. I digress.
Here is what the Catholic encyclopedia notes for the original Cisterican liturgy:
"In the old missal before the reform of Claude Vaussin, there were wide divergences between the Cistercian and Roman rites. The psalm "Judica" was not said, but in its stead was recited the "Veni Creator"; the "Indulgentiam" was followed by the "Pater" and "Ave", and the "Oramus te Domine" was omitted in kissing the altar. After the "Pax Domini sit semper vobiscum", the "Agnus Dei" was said thrice, and was followed immediately by "Hæc sacrosancta commixtio corporis", said by the priest while placing the small fragment of the Sacred Host in the chalice; then the "Domine Jesu Christe, Fili Dei Vivi" was said, but the "Corpus Tuum" and "Quod ore sumpsimus" were omitted. The priest said the "Placeat" as now, and then "Meritis et precibus istorum et onmium sanctorum. Suorum misereatur nostri Omnipotens Dominus. Amen", while kissing the altar; with the sign of the Cross the Mass was ended."
The reason that I bring this up is because I am endeavouring to find either a PDF, a reprinting in a book, or someone with access to the original missal text and a photocopier, of either the entire Missale Cisterciense from prior to 1647, or at very least the Ordo Missae of the same.