Transferring from Latin to Greek Rite Forbidden

20. When Union was effected at the Council of Florence, some Latin Catholics living in Greece thought that it was lawful for them to go over to the Greek rite. They may have been attracted by the freedom retained by the Greeks for priests to keep wives after Ordination if they were married before being ordained. But Pope Nicholas V carefully applied a timely remedy to this abuse: "It has come to Our attention that many Catholics in districts with a Greek Catholic bishop are shamelessly going over to the Greek rites under pretext of the Union. We are greatly astonished, since We do not know what inspired them to leave the practice and rites in which they were born and reared for foreign rites. Even though the rites of the oriental church are praiseworthy, it is not permitted to confuse the rites of the churches. The holy council of Florence never allowed this" (constitution in Bullarii recenter Romae editi, vol. 3, part 3, p. 64).

Since the Latin rite is the rite of the holy Roman church and this church is mother and teacher of the other churches, the Latin rite should be preferred to all other rites. It follows that it is not lawful to transfer from the Latin to the Greek rite. Nor may those who have come over to the Latin rite from the Greek or Oriental rite return again to the Greek Rite, unless particular circumstances occasion the giving of a dispensation (constitution Etsi Pastoralis 57, sect. 2, no. 13, in Our Bullarii, vol. 1). Such dispensations have sometimes been given in times past, and are still given in the Roman College of the Maronites. When a priest there enters the Society of Jesus, he is given a dispensation to transfer to the Latin rite, and sometimes he receives an additional dispensation to say Mass and perform his Divine Office in the church of this College in the Syrian and Chaldaean rite in order to teach this rite to the students there. This is quite clear from many Decrees of the Congregation of the Holy Office, e.g. the Decrees of December 30, 1716; December 14, 1740; and the more recent Decree of August 19, 1752.