Bouyer on the neologism "Paschal mystery"

"Everyone today imagines it [('Paschal mystery')] was a current expression among the Fathers of the Church and the Middle Ages.  In fact, however, as I pointed out to no effect, while Christian Latin does have Paschale sacramentum, it does not have mysterium paschale; furthermore, there has never been an equivalent formula in Greek.  Today I derive bitter satisfaction from this mistake, for it is so symbolic of the misunderstandings that would never cease disfiguring, and finally paralyzing, the intended movement."

     Louis Bouyer, The memoirs of Louis Bouyer, trans. John Pepino (Kettering, OH:  Angelico Press, 2015 [2014]), chap. 9, p. 156.  It was Roguet who proposed the title for the book published in 1947 (Le mystère pascal (paschale sacramentum):  Méditation sur la liturgie des trois derniers jours de la semaine sainte), and therefore Bouyer who must have insisted on the inclusion of "paschale sacramentum".  I have not verified this claim in the great databases unavailable to Bouyer, e.g. the Library of Latin Texts and the Thesaurus Linguae Graecae.  But as Pepino notes, it "ended up being the title of Paul VI's Apostolic Letter 'Mysterii Paschalis' (14 February 1969) approving the new universal norms of the liturgical year and the new General Roman Calendar" (156n36).