But, in fact, the ecclesiastical Latin noun "missa" "mass" is itself derived from the "missa" in this liturgical formula. Also Du Cange (1678) reports "various opinions on the origin" of the noun "missa" "mass". Fortescue (1910) cites more "fanciful" etymological explanations, notably a latinization of Hebrew "matsâh" (מַצָּה) "unleavened bread; oblation", a derivation favoured in the 16th century by Reuchlin and Luther. It is one of the oldest formulae of the Roman Rite, recorded in "Ordo I" (6th or 7th century). but if the noun "missa" "mass" is to be taken as a derivation from this formula, it must predate the 6th century and may date to as early as the 3rd, "missa" being a re-adoption into written Latin of the spoken Late Latin for "missio". After the twelfth century, accretions began to be added to the Mass after the "Ite, missa est", changing it from a dismissal to a mere formula without relation to actuality. But only in the sixteenth century, with the establishment of the Tridentine Mass (Missal of Pope Pius V), were these accretions officially accepted as part of the Mass. In this revision of the Roman Missal, the "Ite, missa est" was followed by a silent private prayer by the priest, then by the blessing and finally by the reading of what was called the Last Gospel (usually , but since, until the reform of Pope Pius X, saints' feasts came to supplant most Sunday Masses, the Last Gospel on such Sundays was that of the Sunday Mass). With the reform of Pope Paul VI "Ite, missa est" returned to its function as a dismissal formula. It is omitted if another function follows immediately and the people are therefore not dismissed. "Ite missa est", not being variable like the Scripture readings and the collect, is part of the Order of Mass and has always been printed in that part of the Roman Missal. Being sung by an individual (ideally the deacon), not by a choir, it cannot be part of a polyphonic musical setting of the Mass. Only the "Deo gratias" response could be set polyphonically but again, because of its brevity, it rarely was, except in some early settings such as Machaut's "Messe de Nostre Dame".