A Missa bifaciata (Latin for 'twice-performed Mass') or Missa trifaciata (Latin for 'thrice-performed Mass') was a type of Mass wherein the priest would pray the texts of the Mass of the Catechumens multiple times.[1]
This practice was common in the late Middle Ages when it was used on days with multiple liturgical feasts, such as when the feast day of a saint coincided with a Sunday, and the celebration of a second Mass by a priest was not possible due to restrictions against bination.[2] It also allowed the fulfillment of several Mass intentions on one day.[1] In a Missa bifaciata, the texts of two Masses (or three, in the case of a Missa trifaciata) from the beginning up to Offertory[3] or the Preface would be prayed. This would then be joined to the Canon of the Mass.[1]
According to Richard Hart, this allowed a priest to receive multiple stipends.[3] This form of Mass was considered an abuse,[1] and was forbidden by mediaeval councils.[4][5]