On this, in 538 Pope Vigilius wrote to Profuturus of Braga: Ordinem quoque precum in celebritate missarum nullo nos tempore, nulla festivitate significamus habere divisum, sed semper eodem tenore oblata Deo munera consecrare. Quoties vero paschalis, aut ascensionis domini, vel pentecostes, et epiphaniae, sanctorumque Dei fuerit agenda festivitas, singula capitula diebus apta subjungimus, quibus commemorationem sanctae solemnitatis, aut eorum facimus, quorum natalitia celebramus: cetera vero ordine consueto prosequimur As to the arrangement of prayers in the celebration of the mass, we intend to have no difference for any time, nor any feast; rather, we mean always to consecrate the gifts offered to God in the same way. Sri Lanka Map Whenever the feasts of Easter, or the Ascension of the Lord, or Pentecost and Epiphany, and the saints of God festivals are to be observed, we add distinct paragraphs appropriate to those days by which we celebrate the commemoration of a holy solemnity, or we celebrate the anniversaries of the saints: we continue with the usual order for the other observances PL 69, 18. The origin of the Roman Canon is an open question, although scholars tend to date it to the time of Pope Damasus I. The language of the canon displays the rhythm and language proper to pre-4th-c. Roman discourse, without the cursus that we find in later orations, esp. at the time of Pope Leo I. The primitive epiclesis also shows the canon’s ancient origin, i.e., before the Eastern pneumatological specifications. The earliest traces of the text are in a partial citation by St. Ambrose in De Sacramentis IV, 21-27, which begins with Fac nobis hanc oblationem scriptam Make for us this written offering and ends with quod tibi obtulit summus sacerdos Melchisedech which is what your High Priest Melchizedek offered. It can be assumed that Ambrose also knew a form of a preface and a petition, since in De Sacram. IV, 14 he states: Laus Deo defertur, oratio petitur pro populo, pro regibus, pro caeteris Praise is offered to God, prayer is requested for the people, for kings, for the rest. The present text of the canon is virtually that of St. Gregory Botte-Mohrmann, L’ordinaire de la messe, 15-25.