The Pentecost Exsultet
From time immemorial, it has been the custom of the Roman Rite to celebrate Pentecost as a baptismal feast on a par with Easter. At the end of the fourth century, Pope St Siricius (384-99) wrote in a letter to a Spanish bishop that the sacrament of baptism was to be celebrated on Pentecost as on Easter. (Epist. ad Himerium, cap. 2: PL XIII, 1131B-1148A) Pope St Leo I (440-61) reasserted that this was the Church’s practice in a letter to the bishops of Sicily, exhorting them to follow the example of the Apostle Peter, who baptized three-thousand persons on Pentecost day. (Epist. XVI ad universos episcopos per Siciliam constitutos: PL LIV, 695B-704A)
As we would expect, therefore, all pertinent liturgical books of the Roman Rite, going as far back as we have them, reflect this tradition. For example, the very oldest collection of Roman liturgical texts, the so-called Leonine Sacramentary, ca. 550 A.D., contains a Mass “on Pentecost, for those coming up from the font.” All Roman lectionaries …