On 7 July 2007, Pope Benedict XVI promulgated Apostolic Letter motu proprio Summorum Pontificum, providing inter alia nearly universal faculties for use of the 1962 Missale Romanum. In his accompanying letter Con grande fiducia, he referred to the 1962 Roman Missal as the Extraordinary Form and the Roman Missal revised following the Second Vatican Ecumenical Council the Ordinary Form. Furthermore, he referred to these as two liturgical Forms of one Latin Rite. At the same time, he called for

more »

... t has become known as "mutual enrichment" between the two liturgical Forms. In this, he specifically invited the addition of Eucharistic Prefaces and the celebration of more recently canonized Saints into the 1962 Roman Missal. He called conceptually for a renewed sacralization of the Ordinary Form by the Extraordinary Form. This study seeks to contribute a comprehensive juridical history of the development of mutual liturgical enrichment, which also serves the purpose of placing the matter in juridic and historical context (Chapter I). Furthermore, it examines the development of the Eucharistic Prefaces and Roman Calendar to, in turn, develop an understanding of what of these elements could be added to the Extraordinary Form in a way that is consistent with its development since the reforms following the Ecumenical Council of Trent (Chapters II and III). Finally, this work seeks to contribute to the field by developing a way of determining what could be used to enrich the Ordinary Form licitly so that various disputed matters, such as who has the authority to make changes to the Mass liturgy, may be resolved, in some cases even by the celebrant himself (Chapter IV).