The Eastern Catholic Churches are autonomous (in Latin, sui iuris) particular Churches in full communion with the Bishop of Rome — the Pope. They preserve the liturgical, theological and devotional traditions of the various Eastern Christian Churches with which they are associated, and between which doctrinal differences exist, in particular between the Eastern Orthodox Church, Oriental Orthodoxy and the Assyrian Church of the East. They thus vary with regard to forms of liturgical worship, sacramental and canonical discipline, terminology, traditional prayers and practices of piety. But they recognize that their faith is not at variance with that of the other constituent Churches of the one Catholic Church, including the Latin or Western Church, all of which are of equal dignity. In particular, they recognize the central role of the Bishop of Rome within the College of Bishops. They preserve the special emphases and illuminations that Eastern Christianity has developed over the centuries, some of which Pope John Paul II illustrated in his apostolic letter Orientale Lumen of 2 May 1995.
Most Eastern Catholic Churches have counterparts in other Eastern Churches, whether Assyrian or Oriental Orthodox, from whom they are separated by a number of theological concerns, or the Eastern Orthodox Churches, from whom they are separated primarily by differences in understanding of the role of the Bishop of Rome within the College of Bishops.
The Eastern Catholic Churches were located historically in Eastern Europe, the Asian Middle East, Northern Africa and India, but are now, because of migration, found also in Western Europe, the Americas and Oceania to the extent of forming full-scale ecclesiastical structures such as eparchies, alongside the Latin dioceses. One country, Eritrea, has only an Eastern Catholic hierarchy, with no Latin structure.
The terms Byzantine Catholics and Greek Catholic are used of those who belong to Churches that use the Byzantine liturgical rite. The terms Oriental Catholic and Eastern Catholic include these, but are broader, since they also cover Catholics who follow the Alexandrian, Antiochian, Armenian and Chaldean liturgical traditions.
The term Eastern Catholic Churches refers to 22 of the 23 autonomous particular Churches in communion with the Bishop of Rome. (Every diocese is a particular Church, but not an autonomous one in the sense in which the word is applied to these 22 Churches.) They follow different Eastern Christian liturgical traditions: Alexandrian, Antiochian, Armenian, Byzantine and Chaldean. Canonically, each Eastern Catholic Church is sui iuris or autonomous with respect to other Catholic Churches, whether Eastern or Latin, though all accept the spiritual and juridical authority of the Pope. Thus a Maronite Catholic is normally subject only to a Maronite bishop, not, for example to a Ukrainian or Latin Catholic bishop. However, if in a country the members of some particular Church are so few that no hierarchy of their own has been established there, their spiritual care is entrusted to a bishop of another ritual Church. This holds also for Latin Catholics: in Eritrea, they are placed in the care of bishops of the Ethiopic Catholic Church. Theologically, all the particular Churches can be viewed as "sister Churches". According to the Second Vatican Council these Eastern Churches, along with the larger Latin Church share "equal dignity, so that none of them is superior to the others as regards rite and they enjoy the same rights and are under the same obligations, also in respect of preaching the Gospel to the whole world (cf. Mark 16:15) under the guidance of the Roman Pontiff."
The Eastern Catholic Churches are in full communion of faith and of acceptance of authority of the See of Rome, but retain their distinctive liturgical rites, laws and customs, traditional devotions and have their own theological emphases. Terminology may vary: for instance, diocese and eparchy, vicar general and protosyncellus, confirmation and chrismation are respectively Western and Eastern terms for the same realities. The mysteries (sacraments) of baptism and chrismation are generally administered, according to the ancient tradition of the Church, one immediately after the other. Infants who are baptized and chrismated are also given the Eucharist.
The Eastern Catholic Churches are represented in the Holy See and the Roman Curia through the Congregation for the Oriental Churches, which, as indicated on the Vatican website, "is made up of a Cardinal Prefect (who directs and represents it with the help of a Secretary) and 27 Cardinals, one Archbishop and 4 Bishops, designated by the Pope ad qui[n]quennium. Members by right are the Patriarchs and the Major Archbishops of the Oriental Churches and the President of the Pontifical Council for the Promotion of Unity among Christians."
Eastern Catholics are in full communion with the Roman Pontiff, and in this sense are members of the Roman Catholic Church, but some feel they are not "Roman Catholics" in the narrower senses of that term, since they are not members of the local particular Church of Rome nor of the Western or Latin Church, which uses the Latin liturgical rites, among which the Roman Rite is the most widespread. Other Eastern Catholics "are proud to call themselves Roman Catholics".
The Code of Canons of the Eastern Churches defines the terms autonomous Church and rite: "A group of Christian faithful linked in accordance with the law by a hierarchy and expressly or tacitly recognized by the supreme authority of the Church as autonomous is in this Code called an autonomous Church" (canon 27); and "1. A rite is the liturgical, theological, spiritual and disciplinary patrimony, culture and circumstances of history of a distinct people, by which its own manner of living the faith is manifested in each autonomous [sui iuris] Church. 2. The rites treated in this code, unless otherwise stated, are those which arise from the Alexandrian, Antiochene, Armenian, Chaldean and Constantinopolitan traditions" (canon 28) In the past, the Eastern Catholic Churches have sometimes been referred to as "Eastern Rites." The Second Vatican Council spoke of them as "particular Churches or rites." The older Latin Code of Canon Law, when speaking of the Eastern Churches, uses the terms "ritual Church"or "ritual Church sui iuris" (canons 111 and 112), and also speaks of "a subject of an Eastern rite"(canon 1015 §2), "Ordinaries of another rite" (canon 450 §1), "the faithful of a specific rite" (canon 476), etc. The use of the term "rite" to refer to the Eastern Churches, and the Western, has now become rare, however. A publication of the National Catholic Council of Catholic Bishops explains: "We have been accustomed to speaking of the Latin (Roman or Western) Rite or the Eastern Rites to designate these different Churches. However, the Church's contemporary legislation as contained in the Code of Canon Law and the Code of Canons of the Eastern Churches makes it clear that we ought to speak, not of rites, but of Churches. Canon 112 of the Code of Canon Law uses the phrase 'autonomous ritual Churches' to designate the various Churches." A periodical of January 2006 declared: "The Eastern Churches are still mistakenly called 'Eastern-rite' Churches, a reference to their various liturgical histories. They are most properly called Eastern Churches, or Eastern Catholic Churches."
Care must indeed be taken to distinguish differing meanings of the word "rite". Apart from its reference to the patrimony of a particular Church, the word has been and sometimes, even if rarely, is still used of the particular Church itself. Thus, the term Latin rite can refer either to the Latin Church or to one or more of the Latin liturgical rites, which include the majority Roman Rite, but also the Ambrosian Rite, the Mozarabic Rite, and others.
The term Uniat or Uniate is applied to those Eastern Catholic churches who were previously Eastern Orthodox churches, and to their members, primarily by Eastern Orthodox. The term is now considered to have a negative, even derogatory, connotation, though it was also historically used, even if less frequently, by Latin and Eastern Catholics, especially prior to the Second Vatican Council. Official Catholic documents no longer use the term, due to its perceived negative overtones. According to Eastern Orthodox Professor John Erickson of St Vladimir's Theological Seminary, "The term 'uniate' itself, once used with pride in the Roman communion, had long since come to be considered as pejorative. 'Eastern Rite Catholic' also was no longer in vogue because it might suggest that the Catholics in question differed from Latins only in the externals of worship. The Second Vatican Council affirmed rather that Eastern Catholics constituted churches, whose vocation was to provide a bridge to the separated churches of the East."
Most Eastern Catholic Churches arose when a group within an ancient Christian Church that was in disagreement with the see of Rome chose to enter into full communion with that see. However, the Maronite Church claims never to have been separated from Rome, and has no counterpart Orthodox Church out of communion with the Pope. It is therefore inaccurate to refer to it as a "Uniate" Church. The Italo-Albanian Catholic Church has also never been out of communion with Rome, but, unlike the Maronite Church, it uses the same liturgical rite as the Eastern Orthodox Churches. The Syro-Malabar Church, based in Kerala, India, also claims never to have been knowingly out of communion with Rome. Other Christians of Kerala, who were originally of the same East-Syrian tradition, passed instead to the West-Syrian tradition and now form part of Oriental Orthodoxy (some from the Oriental Orthodox in India reunited with the Catholic Church in 1930 and became the Syro-Malankara Catholic Church).
The canon law that the Eastern Catholic Churches have in common has been codified in the 1990 Code of Canons of the Eastern Churches. Within the Roman Curia, the dicastery that works with the Eastern Catholic Churches is the Congregation for the Oriental Churches, which, by law, includes as members all Eastern Catholic patriarchs and major archbishops.
All Catholics are subject to the bishop of the eparchy or diocese (the local particular Church) to which they belong. They are also subject directly to the Pope, as is stated in canon 43 of the Code of Canons of the Eastern Churches and canon 331 of the Code of Canon Law. Most, but not all, Eastern Catholics are also directly subject to a patriarch, major archbishop/Catholicos, or metropolitan who has authority for all the bishops and the other faithful of the autonomous particular Church (canons 56 and 151 of the Code of Canons of the Eastern Churches).
Under the Code of Canons of the Eastern Churches, the Roman Pontiff (the Pope) enjoys supreme, full, immediate and universal ordinary power in the Church which he can always freely exercise. The full description is under Title 3, Canons 42 to 54 of the Code of Canons of the Eastern Churches.
The Catholic patriarchs and major archbishops derive their titles from the sees of Alexandria (Copts), Antioch (Syrians, Melkites, Maronites), Babylonia (Chaldaeans), Cilicia (Armenians), Kyiv-Halych (Ukrainians), Ernakulam-Angamaly (Syro-Malabars), Trivandrum (Syro-Malankaras), and Făgăraş-Alba Iulia (Romanians). The Eastern Churches, their leaders and synods are governed under Titles 4, 5, 6, 7, 8 and 9, respectively, under the Code of Canons of the Eastern Churches. 
Communion between Christian Churches has been broken over matters of faith, when each side accused the other of heresy or departure from the true faith (orthodoxy). Communion has been broken also because of disputes that do not involve matters of faith, as when there is disagreement about questions of authority or the legitimacy of the election of a particular bishop. In these latter cases, each side accuses the other of schism, but not of heresy.
Major breaches of communion:
At a meeting in Balamand, Lebanon in June 1993, the Joint International Commission for the Theological Dialogue between the Roman Catholic Church and the Orthodox Church declared that these initiatives that "led to the union of certain communities with the See of Rome and brought with them, as a consequence, the breaking of communion with their Mother Churches of the East ... took place not without the interference of extra-ecclesial interests" (section 8 of the document). Likewise, the Commission acknowledged that "unacceptable means" were used in attempts to force Eastern Catholics to return to the Orthodox Church (section 11). The missionary outlook and proselytism that accompanied the Unia (section 10), was recognized to be incompatible with the rediscovery of each other as "Sister Churches" (section 12). Thus, the Commission concluded that the "missionary apostolate ... which has been called 'uniatism', can no longer be accepted either as a method to be followed nor as a model of the unity our Churches are seeking (section 12).
At the same time, the Commission stated:
As remarked earlier, the identity of the Maronite Church and of the Syro-Malabar Church is due to no such division within an Eastern Church.
Eastern Catholic Churches make up 2% of the membership of the Catholic Church when compared to the Latin Rite which has over one billion members. The 2008 statistics collected by the CNEWA show that Syriac Christians make up 47% of Eastern Catholics and Byzantine Christians make up 46%. The largest particular church is the Ukrainian Greek Catholic Church with 25% and second largest is the Syro-Malabar at 23%. The majority of Syriac rite Christians (western or eastern) are Catholic.
On 30 November 1894 Pope Leo XIII issued the Apostolic Constitution Orientalium Dignitas, in which he says "that the ancient Eastern rites are a witness to the Apostolicity of the Catholic Church, that their diversity, consistent with unity of the faith, is itself a witness to the unity of the Church, that they add to her dignity and honour. He says that the Catholic Church does not possess one rite only, but that she embraces all the ancient rites of Chistendom; her unity consists not in a mechanical uniformity of all her parts, but on the contrary, in their variety, according in one principle and vivified by it."
The Pope broadened from Melkite Catholics to all Eastern Catholics the prohibition in Pope Benedict XIV's Constitution Demandatam or 24 December 1743, declaring: "Any Latin rite missionary, whether of the secular or religious clergy, who induces with his advice or assistance any Eastern rite faithful to transfer to the Latin rite, will be deposed and excluded from his benefice in addition to the ipso facto suspension a divinis and other punishments that he will incur as imposed in the aforesaid Constitution Demandatam."
Starting in 1964, a series of reforms have been issued concerning Eastern Catholic Churches that have corrected a number of past errors. The cause of those reforms were behaviors that had been building for quite some time, especially below the papal level.
The lack of complete lasting effect of Pope Leo XIII's 1894 encyclical Orientalium Dignitas even with latin clergy being rather firmly threatened to cease and desist from raiding believers from other rites (as the sui iuris Churches were called at the time) led to a gradual awakening to the need to overhaul the relationship between the churches of the East and the West. During this period, attempts at partial and total suppression led to schism in America. and difficulties everywhere. Separated Eastern Churches were not slow to issue "I told you so's". There was confusion as to the universality of the Churches of the East among Western clergy despite firm and repeated papal confirmation of these Churches universal character over the centuries. Vatican II brought the reform impulse to visible fruition. Several documents, both during and after Vatican II have led to significant reform and development within the Eastern Catholic Churches.
See main article: Orientalium Ecclesiarum. In the decree Orientalium Ecclesiarum (21 November 1964), dealing with the Churches of Eastern Christianity, the Second Vatican Council directed that the traditions of the Eastern Catholic Churches should be maintained. It declared that "it is the mind of the Catholic Church that each individual Church or Rite should retain its traditions whole and entire and likewise that it should adapt its way of life to the different needs of time and place" (section 2), and that they should all "preserve their legitimate liturgical rite and their established way of life, and ... these may not be altered except to obtain for themselves an organic improvement" (section 6; cf. 22). It confirmed and approved the ancient discipline of the sacraments existing in the Eastern Churches, as also the ritual practices connected with their celebration and administration, and declared its ardent desire that this should be re-established, if circumstances warranted (section 12). It applied this in particular to administration of Confirmation by priests (section 13). It expressed the wish that, where the permanent diaconate (ordination as deacons of men who are not intended afterwards to become priests) had fallen into disuse, it should be restored (section 17). Sections 7-11 are devoted to the powers of the patriarchs and major archbishops of the Eastern Churches, whose rights and privileges, it says, should be re-established in accordance with the ancient tradition of each of the Churches and the decrees of the ecumenical councils, adapted somewhat to modern conditions. Where there is need, new patriarchates should be established either by an ecumenical council or by the Roman Pontiff.
The Council's dogmatic constitution on the Church, Lumen Gentium (21 November 1964) deals with the Eastern Catholic Churches in section 23. Its states:
By divine Providence it has come about that various churches, established in various places by the apostles and their successors, have in the course of time coalesced into several groups, organically united, which, preserving the unity of faith and the unique divine constitution of the universal Church, enjoy their own discipline, their own liturgical usage, and their own theological and spiritual heritage. Some of these churches, notably the ancient patriarchal churches, as parent-stocks of the Faith, so to speak, have begotten others as daughter churches, with which they are connected down to our own time by a close bond of charity in their sacramental life and in their mutual respect for their rights and duties. This variety of local churches with one common aspiration is splendid evidence of the catholicity of the undivided Church. In like manner the Episcopal bodies of today are in a position to render a manifold and fruitful assistance, so that this collegiate feeling may be put into practical application.
The decree Unitatis Redintegratio (also of 21 November 1964) deals with the Eastern Catholic Churches in sections 14-17.
During the First Vatican Council the need for a common code for the Eastern Churches was discussed, but no concrete action was taken. Only after the benefits of the 1917 Latin code were appreciated was a serious effort made to create a similar code for the Eastern Catholic Churches. This came to fruition with the promulgation in 1990 of the Code of Canons of the Eastern Churches, which came into effect in 1991. It is a framework document that lays out the canons that are a consequence of the common patrimony of the Churches of the East: each individual sui iuris Church has its own canons, its own particular law, layered on top of this code.
The Instructions of 6 January 1996 are intended to bring together in one place the developments that took place in the previous texts. The 'Instruction' is "an expository expansion based upon the canons, with constant emphasis upon the preservation of Eastern liturgical traditions and a return to those usages whenever possible - certainly in preference to the usages of the Latin church, however much some principles and norms of the conciliar constitution on the Roman rite, 'in the very nature of things, affect other rites as well'." As the Instruction itself puts it:
The liturgical laws valid for all the Eastern Churches are important because they provide the general orientation. However, being distributed among various texts, they risk remaining ignored, poorly coordinated and poorly interpreted. It seemed opportune, therefore, to gather them in a systematic whole, completing them with further clarification: thus, the intent of the Instruction, presented to the Eastern Churches which are in full communion with the Apostolic See, is to help them fully realize their own identity. The authoritative general directive of this Instruction, formulated to be implemented in Eastern celebrations and liturgical life, articulates itself in propositions of a juridical-pastoral nature, constantly taking initiative from a theological perspective.These modern developments were necessitated by a series of less than stellar initiatives in the past.
These interventions felt the effects of the mentality and convictions of the times, according to which a certain subordination of the non-Latin liturgies was perceived toward the Latin-rite liturgy which was considered "ritus praestantior." This attitude may have led to interventions in the Eastern liturgical texts which today, in light of theological studies and progress, have need of revision, in the sense of a return to ancestral traditions. The work of the commissions, nevertheless, availing themselves of the best experts of the times, succeeded in safeguarding a major part of the Eastern heritage, often defending it against aggressive initiatives and publishing precious editions of liturgical texts for numerous Eastern Churches. Today, particularly after the solemn declarations of the Apostolic Letter Orientalium Dignitas by Leo XIII, after the creation of the still active special Commission for the liturgy within the Congregation for the Eastern Churches in 1931, and above all after the Second Vatican Council and the Apostolic Letter Orientale Lumen by John Paul II, respect for the Eastern liturgies is an indisputable attitude and the Apostolic See can offer a more complete service to the Churches.
The Holy See's Annuario Pontificio gives the following list of Eastern Catholic Churches and of countries (or other political areas, consisting of more than country) in which they possess an episcopal ecclesiastical jurisdiction (date of union or foundation in parenthesis):
(two apostolic exarchates, at present with no published hierarchs): Russia, China (1905); currently about 20 parishes and communities scattered around the world, including five in Russia itself, answering to bishops of other jurisdictions
Note: Georgian Byzantine-Rite Catholics are not recognized as a particular Church (cf. canon 27 of the Code of Canons of the Eastern Churches). The majority of Eastern Catholic Christians in the Georgian Republic worship under the form of the Armenian liturgical rite.
As is obvious from the above list, an individual autonomous particular Church may have distinct jurisdictions (local particular Churches) in several countries.
The Ruthenian Catholic Church is organized in an exceptional way because of a constituent metropolia, the Byzantine Catholic Metropolitan Church of Pittsburgh, which is referred to also, but not officially, as the Byzantine Catholic Church in America. Canon law treats it as if it held the rank of an autonomous ("sui iuris") metropolitan particular Church because of the circumstances surrounding its 1969 erection as an ecclesiastical province.
At that time, conditions in the Rusyn homeland, known as Carpatho-Rus, admitted no other solution because the Byzantine Catholic Church had been forcibly suppressed by the Soviet authorities. When Communist rule ended, the Eparchy of Mukacheve (founded in 1771) re-emerged.
It has some 320,000 adherents, greater than the number in the Pittsburgh metropolia. In addition, an apostolic exarchate established in 1996 for Catholics of Byzantine rite in the Czech Republic is classed as another part of the Ruthenian Catholic Church.
On an EWTN website the Apostolic Exarchate for Byzantine-rite Catholics in the Czech Republic is mentioned in a list of Eastern Churches, of which all the rest are autonomous particular Churches. This appears to be a mistake, since recognition within the Catholic Church of the autonomous status of a particular Church can only be granted by the Holy See (cf. canon 27 of the Code of Canons of the Eastern Churches), which instead classifies this Church as one of the constituent local particular Churches of the autonomous (sui iuris) Ruthenian Catholic Church.
See main article: Georgian Byzantine-Rite Catholics.
Some have treated Byzantine-rite Catholics within the Georgian Catholic Church as a separate particular Church with a reunion date of either 1861 or 1917. A study by Deacon Methodios Stadnik states: "The Georgian Byzantine Catholic Exarch, Fr. Shio Batmanishviii (sic), and two Georgian Catholic priests of the Latin rite were executed by the Soviet authorities in 1937 after having been held in captivity in Solovki prison and the northern gulags from 1923." In his book The Forgotten: Catholics of the Soviet Union Empire from Lenin through Stalin, Father Christopher Zugger writes: "By 1936, the Byzantine Catholic Church of Georgia had two communities, served by a bishop and four priests, with 8,000 believers", and he identifies the bishop as Shio Batmalashvili. The Ukrainian Helsinki Human Rights Union mentions "the Catholic administrator for Georgia Shio Batmalashvili" as one of those who were executed as "anti-Soviet elements" in 1937.
The second of these sources calls Batmalashvili a bishop. The first is ambiguous, calling him an Exarch but giving him the title of Father. The third merely refers to him as "the Catholic administrator" without specifying whether he was a bishop or a priest and whether he was in charge of a Latin or a Byzantine-rite jurisdiction.
If Batmalashvili was an Exarch, and not instead a bishop connected with the Latin diocese of Tiraspol, which had its seat at Saratov on the Volga River, to which Georgian Catholics even of Byzantine rite belonged  this would mean that a Georgian Byzantine-Rite Catholic Church existed, even if only as a local particular Church. However, since the establishment of a new hierarchical jurisdiction must be published in the Acta Apostolicae Sedis, and no mention of the erection of such a jurisdiction for Byzantine Georgian Catholics exists in that official gazette of the Holy See, the claim appears to be unfounded.
The Annuario Pontificio, which normally lists all the bishops of the Catholic Church, does not mention Batmalashvili in its editions of the 1930s. If indeed he was a bishop, he may then have been one of the priests secretly ordained bishops of titular sees for the service of the Church in the Soviet Union by French Jesuit Bishop Michel d'Herbigny, who was head of the Pontifical Commission "Pro Russia" from 1925 to 1934, and who perhaps were given exclusive jurisdiction for no particular area of the Soviet Union. In the circumstances then prevailing, the Holy See would have been incapable of and would not even have thought of setting up new dioceses or exarchates within the Soviet Union, especially not of Byzantine rite, since Byzantine-rite Catholics were being forced to become officially members of the Russian Orthodox Church.
Batmalashvili's name is not among those given in Roman Catholic Regional Hierarchy as the four "underground" apostolic administrators (only one of whom appears to have been a bishop) for the four sections into which the diocese of Tiraspol was divided after the resignation in 1930 of its already exiled last bishop, Joseph Aloysius Kessler. This source gives Father Stefan Demurow as apostolic administrator of "Tbilisi and Georgia" and says he was executed in 1938. Other sources associate Father Demurow with Azerbaijan and say that, rather than being executed, he died in a Siberian concentration camp.
Until 1994, the annual publication Catholic Almanac used to go further, listing "Georgian" among the Byzantine Rites or autonomous particular Churches. Until corrected in 1995, it appears to have been making a mistake similar to that made on the equally unofficial EWTN site about the Czech Byzantine-rite Catholics.
There was also a short-lived Byzantine Catholic movement among the ethnic Estonians in the Orthodox Church in Estonia during the inter-war period of the twentieth century, consisting of two to three parishes, not raised to the level of a local particular church with its own head. This group was liquidated by the Soviet regime and is now extinct.
While "clerics and members of institutes of consecrated life are bound to observe their own rite faithfully," priests are occasionally given permission to celebrate the liturgy of a rite other than the priest's own rite, by what is known as a grant of "biritual faculties". The reason for this permission is usually the service of Catholics who have no priest of their own rite. Thus priests of the Syro-Malabar Church working as missionaries in areas of India in which there were no structures of their own Church, were authorized, while remaining priests of the Syro-Malabar Church, to use the Roman Rite in those areas, and Latin-Rite priests are, after due preparation, given permission to use an Eastern rite for the service of members of an Eastern Catholic Church living in a country in which there are no priests of their own particular Church.
The Pope, to whose pastoral guidance the individual Churches both Eastern and Western are all equally entrusted, can celebrate the liturgy according to any rite. However, because he is Bishop of Rome, he normally uses the Roman Rite.
For a just cause (especially in order to foster Christian love and manifest the unity between the different particular Churches) and with the permission of the local bishop, priests of different autonomous ritual Churches may concelebrate, using strictly, without admixture, the rite of the principal celebrant; it is preferable that each wears the vestments of his own rite. For this no indult of biritualism is required.
Biritual faculties may concern not only clergy but also religious, enabling them to become members of an institute of an autonomous Church other than their own.
The laity are obliged to foster an understanding and appreciation of their own rite, and are held to observe it everywhere unless something is excepted by the law. This does not forbid occasional or even, for a just cause, habitual participation in the liturgy of a different autonomous Church, Western or Eastern. The obligation of assisting at the Eucharist or, for members of some Eastern Churches, at Vespers, is satisfied wherever the liturgy is celebrated in a Catholic rite.
Eastern and Western Christian churches have different traditions concerning clerical celibacy. These differences and the resulting controversies have played a role in the relationship between the two groups in some Western countries.
Most Eastern Churches distinguish between "monastic" and "non-monastic" clergy. Monastics do not necessarily live as monks or in monasteries, but have spent at least part of their period of training in such a context. Their monastic vows include a vow of celibate chastity.
Bishops are normally selected from the monastic clergy, and in most Eastern Churches a large percentage of priests and deacons also are celibate, while a portion of the clergy (typically, parish priests) may be married. If a future priest or deacon is to be married, his marriage must take place before ordination to the diaconate. While in some countries the marriage continues usually to be arranged by the families, cultural changes sometimes make it difficult for such seminarians to find women prepared to be the wife of a priest, necessitating a hiatus in the seminarians' studies.
In countries where Eastern traditions prevail among Christians, a married clergy caused little controversy; but it aroused opposition in other countries to which Eastern Catholics immigrated. In response to requests from the Latin bishops of those countries, the Sacred Congregation for the Propagation of the Faith set out rules in a letter of 2 May 1890 to François-Marie-Benjamin Richard, the Archbishop of Paris, which the Congregation applied on 1 May 1897 to the United States, stating that only celibates or widowed priests coming without their children should be permitted in the United States. This rule was restated with special reference to Catholics of Ruthenian Rite by the 1 March 1929 decree Cum data fuerit, which was renewed for a further ten years in 1939. Dissatisfaction by many Ruthenian Catholics in the United States gave rise to the American Carpatho-Russian Orthodox Diocese. This rule was abolished with the promulgation of the Decree on the Catholic churches of the Eastern Rite; since then, married men have been ordained to the priesthood in the United States, and numerous married priests have come from eastern countries to serve parishes in the Americas.
Some Eastern Catholic Churches have decided to adopt mandatory clerical celibacy, as in the Latin Church. They include the Syriac Catholic Church, the Syro-Malankara Catholic Church and the Ethiopic Catholic Church.