Joint International Commission for Theological Dialogue Between the Catholic Church and the Orthodox Church
For Catholics, the convocation of the Second Vatican Council at which Orthodox observers were present marked a new beginning. A positive evaluation of the eastern tradition is found in the Council documents, especially Unitatis redintegratio. Most importantly, it clearly states that the Orthodox are "churches" in the full sense of the word, and that they have valid sacraments. This laid the foundation for the development of an ecclesiology of communion and the notion that Catholics and Orthodox are "sister churches".
This coincided with the development of what became known as the "dialogue of charity", a process of learning to trust one another again, a necessary precursor of any fruitful theological dialogue. In January 1964, Pope Paul VI and Patriarch Athenagoras I of Constantinople met for the first time, in Jerusalem. On December 7, 1965, in Rome and Istanbul they issued the Catholic–Orthodox Joint Declaration of 1965, simultaneously proclaiming the lifting of the mutual excommunications of 1054 and declaring them "erased from the memory" of the church. These steps were the prelude to the establishment of the theological commission by Pope John Paul II and Patriarch Dimitrios I of Constantinople in 1979.
The commission's first ten years of work reflected the growing consensus between the two communions and saw the publication of three agreed statements on such issues as the relationship between the Trinity, the Church and Eucharist; the sacraments of initiation and the connection between common faith and sacramental communion; and the theology of the ordained ministry.
The commission has held the following plenary sessions:
- 1st Patmos & Rhodes, Greece (1980) "The Mystery of the Church and the Eucharist in the Light of the Mystery of the Holy Trinity"
- 2nd Munich, Germany (June 30 to July 6, 1982) "The Mystery of the Church and the Eucharist in the Light of the Mystery of the Holy Trinity" 
- 3rd Crete, Greece (1984) "Faith, Sacraments and Unity of the Church"
- 4th Bari, Italy (June 9-16, 1987) "Faith, Sacraments and the Unity of the Church"
- 5th Valamo, Finland (June 19-27, 1988) "The Sacrament of Order in the Sacramental Structure of the Church, with Particular Reference to the Importance of the Apostolic Succession for the Sanctification and Unity of the People of God"
- 6th Freising (1990) "Uniatism"
- 7th Balamand, Lebanon (June 17-24, 1993) "Uniatism: Method of Union of the Past, and Present Search for Full Communion"
- 8th Emmitsburg, Maryland, US (July 9-19, 2000)"Ecclesiological and Canonical Implications of Uniatism"
- 9th Belgrade, Serbia (2006) "The Ecclesiological and Canonical Consequences of the Sacramental Nature of the Church; Conciliarity and Authority in the Church at Three Levels of Ecclesial Life: Local, Regional and Universal"
- 10th Ravenna, Italy (October 8-14, 2007)"The Ecclesiological and Canonical Consequences of the Sacramental Nature of the Church – Ecclesial Communion, Conciliarity and Authority" 
- 11th Paphos, Cyprus (2009) "The Role of the Bishop of Rome in the Communion of the Church in the First Millennium"
- 12th Vienna, Austria (2010) "The Role of the Bishop of Rome in the Communion of the Church in the First Millennium"
- 13th Amman, Jordan (2014) "Primacy and synodality in the Church"
- 14th Chieti, Italy (2016) "Primacy and synodality in the Church"
Seventh Plenary Session (Balamand, Lebanon)
The seventh plenary session took place from June 17 to 24th, 1993. The theme of this session was entirely focused on the theological and practical questions presented by the existence and pastoral activity of the Oriental Catholic Churches. The dissolution of the Soviet Union and the attendant collapse of the Warsaw Pact in Central and Eastern Europe brought about "profound changes... involving the rebirth of religious liberty and the resumption of open pastoral activity by the Oriental Catholic Churches". The session declared that these changes had "made these questions the touchstone of the quality of the relations between the Catholic and the Orthodox Churches." In particular, the question of Uniatism became the focus of attention. The document of the joint dialogue commission on the theme: "Uniatism: method of union of the past, and the present search for full communion" declared the following:
- With regard to the method which has been called "uniatism", it was stated at Freising (June 1990) that "we reject it as method for the search for unity because it is opposed to the common tradition of our Churches".
- Concerning the Oriental Catholic Churches, it is clear that they, as part of the Catholic Communion, have the right to exist and to act in answer to the spiritual needs of their faithful.
Eighth Plenary Session (Emmitsburg, United States)
The eighth plenary session of the Joint International Commission for the Theological Dialogue between the Roman Catholic Church and the Orthodox Church was held in Emmitsburg, Maryland, US from July 9 to 19th, 2000.
The theme discussed at this plenary session was the "Ecclesiological and Canonical Implications of Uniatism" based upon the preliminary document prepared in Ariccia/Rome (1998) by the Commission's Coordinating Committee, a subject which had assumed particular importance since the changes which occurred in Central and Eastern Europe over the ten years prior to the meeting.
The Joint International Commission had been particularly concerned with this question since its sixth plenary session in Freising (Germany) in 1990 and in its seventh session in Balamand (Lebanon) in 1993. Documents touching upon theological aspects as well as practical guidelines were issued by the Joint Commission in these meetings. Although reactions were generally positive, the documents were met with some reservations and even outright opposition, sometimes from both sides.
Ninth Plenary Session (Belgrade, Serbia)
The ninth plenary session of the commission was held from 18 September to 25 September 2006 in Belgrade, Serbia.
Tenth Plenary Session (Ravenna, Italy)
The tenth meeting took place in Ravenna, Italy from October 8 to 14th, 2007.
- Eastern Orthodox – Roman Catholic ecclesiastical differences
- Eastern Orthodox – Roman Catholic theological differences
- Pontifical Council for Promoting Christian Unity
- McPartlan, Paul. "Towards Catholic-Orthodox Unity". Communio. 19 (Summer 1992): 305–320.
- "The mystery of the church and of the eucharist in the light of the mystery of the holy Trinity". Vatican.va. Retrieved 2015-09-03.
- "Joint International Commission for the Theological Dialogue between the Roman Catholic Church and the Orthodox Church". Vatican.va. Retrieved 2015-09-03.
- "The Sacrament of Order in the Sacramental Structure of the Church". Vatican.va. Retrieved 2015-09-03.
- "Communiqué from the meeting of the seventh plenary session". Vatican.va. Retrieved 2015-09-03.
- "The Ravenna Document". Vatican.va. Retrieved 2015-09-03.
- "Pro Unione Web Site - Dialogues O-RC". Prounione.urbe.it/dia-int/o-rc/e_o-rc-info.html. Retrieved 2015-09-03.
- "For the Press". Papalvisit.ecupatriarchate.org. Retrieved 2015-09-03.
- Pontifical Council for Promoting Christian Unity
- Pontifical Oriental Institute
- Dialogue with the Orthodox Churches of Byzantine Tradition
- Commission on Catholic-Orthodox Unity Set To Resume
- Catholic, Orthodox Churches To Unite?
- Ecumenical talks reach partial accord on papal primacy November 14, 2007
- The Role of the Bishop of Rome in the Communion of the Church in the First Millennium  Crete, 2008
- Bishop Hilarion Alfeyev: Prospects of Orthodox-Catholic Relations
- Catholic, Orthodox report promising progress on unity Reuters, Sep 24, 2010
- Catholic, Orthodox Move Toward Unity Reuters, 27 September 2010
- Met. Hilarion: No “breakthroughs” in Vienna September 27, 2010
- Catholic-Orthodox talks on papacy: officials optimistic, while Moscow denies breakthrough September 28, 2010