In the later series of Western rituals, beginning with that which is known as the Leonine Sacramentary, this practice is almost universal.
The Roman books are silent, and there is no mention of it in the collection known as the Leonine Sacramentary; while in the so-called Gelasian Massbook, which, as we have it, is full of Gallican additions made to St Gregory's reform, there is the same silence, though in one MS. of the 10th century given by Muratori we find a form for the ordination of an acolyte.
Wilson, The Gelasian Sacramentary (Oxford, 1894); F.
The phrase dies cinerum appears in the earliest extant copies of the Gregorian Sacramentary, and it is probable that the custom was already established by the 8th century.
If we are to credit a 9th century biographer, Gregory abbreviated and otherwise simplified the Sacramentary of Gelasius, producing a revised edition with which his own name has become associated, and which represents the groundwork of the modern Roman Missal.