Sui iuris, commonly also spelled sui juris, is a Latin phrase that literally means “of one’s own laws”.
In civil law the phrase sui juris indicates legal competence, the capacity to manage one’s own affairs (Black's Law Dictionary, Oxford English Dictionary). It also implies someone who is capable of suing and/or being sued in a legal proceeding in their own name, without the need of an ad litem.
Thus in Roman law the caregiver or guardian of a spendthrift (prodigus) or of a person of unsound mind (furiosus), and, particularly, one who takes charge of the estate of an adolescens, i.e. of a person sui juris, above the age of a pupillus, fourteen or twelve years (boys and girls, respectively), and below the full age of twenty-five. Such persons were known as minors, i.e. minores viginti quinque annis. While the tutor, the guardian of the pupillus, was said to be appointed for the care Of the person, the curator took charge of the property.
The English word “autonomous” is derived from the Ancient Greek αυτονόμος (from autos - self, and nomos - law) which corresponds to the Latin "sui iuris".
Examples of secular usage
The Congress of the United States is a good example of a sui juris based institution. The two chambers of the Congress assemble into session by their own right as defined in the US Constitution (Twentieth Amendment) on January 3 every year. The US President does not have to invite or call the Congress to assemble for regular sessions (although he has the option to call special sessions). In the United States, the legislature is independent of the executive (although there are some checks and balances). This is in contrast with many parliamentary democracies like India, where the federal Parliament can assemble if and only if the President of India summons it (on the advice of the Prime Minister). This is because the Indian Constitution is largely based upon the conventions of the British monarchy, in which it was a crime of treason for the English Parliament to assemble without the permission of the King.
Catholic ecclesiastical use
Church documents such as the Code of Canons of the Eastern Churches apply the Latin term sui iuris to the particular Churches that together compose the Catholic Church (i.e., the Roman Catholic Church and those in communion with her). By far the largest of these "sui iuris" or autonomous Churches is that known as the Latin Church or the Latin Rite. Over this particular Church the Pope exercises, as well as his papal authority, the authority that in other particular Churches belongs to a Patriarch. He has therefore been referred to also as Patriarch of the West. The other particular Churches are called Eastern Catholic Churches, each of which, if large enough, has its own patriarch or other chief hierarch, with authority over all the bishops of that particular Church or rite.
The same term is applied also to missions that, though lacking enough clergy to be set up as apostolic prefectures, are for various reasons given autonomy, and thus are not part of any diocese, apostolic vicariate or apostolic prefecture. In 2004, there were eleven such missions: three in the Atlantic, Cayman Islands, Turks and Caicos, and Saint Helena, Ascension and Tristan da Cunha; two in the Pacific, Funafuti (Tuvalu), and Tokelau; and six in central Asia, Afghanistan, Baku (Azerbaijan), Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan.
Examples of Catholic ecclesiastical use
- Mission sui iuris
- "The Eastern Catholic Churches are not 'experimental' or 'provisional' communities; these are sui iuris Churches; One, Holy, Catholic and Apostolic, with the firm canonical base of the Code of Canons of the Eastern Churches promulgated by Pope John Paul II." 
- "The hierarchs of the Byzantine Metropolitan Church sui iuris of Pittsburgh, in tile United States of America, gathered in assembly as the Council of Hierarchs of said Church, in conformity with the Code of Canons of the Eastern Churches, ..." 
- "It would likewise be helpful to prepare a Catechetical Directory that would 'take into account the special character of the Eastern Churches, so that the biblical and liturgical emphasis as well as the traditions of each Church sui iuris in patrology, hagiography and even iconography are highlighted in conveying the catechesis' (CCEO, can. 621, §2)" John Paul II 
- "On behalf of the Kyrgyzstan Catholics I would like to express our gratitude to the Holy Father for his prayers and for all that he has done for us: ... and for the creation of the new 'missioni sui iuris' in Central Asia, in a special way — for the trust placed on the 'Minima Societas Jesu', to which he entrusted the mission in Kyrgyzstan." 
- "...[T]he rays originating in the one Lord, the sun of justice which illumines every man (cf. Jn 1:9), ... received by each individual Church sui iuris, has value and infinite dynamism and constitutes a part of the universal heritage of the Church." "Instruction for Applying the Liturgical Prescriptions of the Code of Canons of the Eastern Churches", issued January 6, 1996 by the Congregation for the Eastern Churches .
Churches sui iuris
The term Church sui iuris is used in CCEO to denote the autonomous churches in Catholic communion.
A church sui iuris is " a community of the Christian faithful, which is joined together by a hierarchy according to the norm of law and which is expressly or tacitly recognized as sui iuris by the supreme authority of the Church"(CCEO.27) . The term sui iuris is an innovation of CCEO (Codex Canonum Ecclesiarum Orientalium - Code of Canons of the Oriental Churches) and it denotes the relative autonomy of the oriental Catholic Churches. This canonical term, pregnant with many juridical nuances, indicates the God-given mission of the Oriental Catholic Churches to keep up their patrimonial autonomous nature. And the autonomy of these churches is relative in the sense that it is under the supreme authority of the Roman Pontiff.
“Una Chiesa Orientale cattolica è una parte della Chiesa Universale che vive la fede in modo corrispondente ad una delle cinque grandi tradizioni orientali- Alessandrina, Antiochena, Costantinopolitina, Caldea, Armena- e che contiene o è almeno capace di contenere, come sue componenti minori, piú communià diocesane gerarchicamente riunite sotto la guida di un capo commune legittimamente eleto e in communione con Roma, il quale con il proprio Sinodo costituisce la superiore istanza per tutti gli affari di carattere amministrativo, legislativo e giudiziario delle stesse Communità, nell'ambitto del diritto commune a tutte le Chiese, determinato nei Canoni sancti dai Concili Ecumenici o del Romano Pontefice, sempre preservando il diritto di quest'ultimo di intervenire nei singoli casi”
Categories of Churches sui iuris
According to CCEO the oriental catholic churches sui iuris are of four categories:
The patriarchal church is the full-grown form of an Eastern Catholic Church. It is a 'a community of the Christian faithful joined together by' a Patriarchal hierarchy. The Patriarch together with the synod of bishops has the legislative, judicial and administrative powers within jurisdictional territory of the patriarchal church, without prejudice to those powers reserved, in the common law to the Roman pontiff (CCEO 55-150). Among the catholic oriental churches the following churches are of patriarchal status:
- Coptic Catholic Church (1741):Cairo, (163,849), Egypt
- Maronite Church (union re-affirmed 1182): Bkerke, (3,105,278), Lebanon, Cyprus, Jordan, Israel, Palestine, Egypt, Syria, Argentina, Brazil, United States, Australia, Canada, Mexico
- Syriac Catholic Church (1781): Beirut,(131,692), Lebanon, Iraq, Jordan, Kuwait, Palestine, Egypt, Sudan, Syria, Turkey, United States and Canada, Venezuela
- Armenian Catholic Church (1742): Beirut, (375,182), Lebanon, Iran, Iraq, Egypt, Syria, Turkey, Jordan, Palestine, Ukraine, France, Greece, Latin America, Argentina, Romania, United States, Canada, Eastern Europe
- Chaldean Catholic Church (1692): Baghdad, (418,194), Iraq, Iran, Lebanon, Egypt, Syria, Turkey, United States
- Melkite Greek Catholic Church (1726): Damascus, (1,346,635), Syria, Lebanon, Jordan, Israel, Jerusalem, Brazil, United States, Canada, Mexico, Iraq, Egypt and Sudan, Kuwait, Australia, Venezuela, Argentina
Major Archiepiscopal Churches
Major archiepiscopal churches are the oriental churches, governed by the Major Archbishops being assisted by the respective synod of Bishops. These churches also have almost the same rights and obligations of Patriarchal Churches. A major archbishop is the Metropolitan of a see determined or recognized by the Supreme authority of the Church, who presides over an entire Eastern Church sui iuris that is not distinguished with the patriarchal title. What is stated in common law concerning patriarchal Churches or patriarchs is understood to be applicable to major archiepiscopal Churches or major archbishops, unless the common law expressly provides otherwise or it is evident from the nature of the matter" (CCEO.151, 152). Following are the Major Archiepiscopal Churhes:
- Syro-Malankara Catholic Church (1930): Trivandrum, (412,640), India, United States of America
- Syro-Malabar Church (1663): Ernakulam, (3,902,089), India, Middle East, Europe and America
- Romanian Church United with Rome, Greek-Catholic (1697): Blaj, (776,529), Romania, United States of America
- Ukrainian Greek Catholic Church (1595): Kiev, (4,223,425), Ukraine, Poland, United States, Canada, Great Britain, Australia, Germany and Scandinavia, France, Brazil, Argentina
The sui iuris church, which is governed by a Metropolitan, is called a Metropolitan church sui iuris. " A Metropolitan Church sui iuris is presided over by the Metropolitan of a determined see who has been appointed by the Roman Pontiff and is assisted by a council of hierarchs according to the norm of law" (CCEO. 155§1). The Catholic Metropolitan churches are the following:
- Ethiopian Catholic Church (1846): Addis Ababa, (208,093), Ethiopia, Eritrea
- Ruthenian Catholic Church (1646) - a sui juris metropolia, an eparchy, and an apostolic exarchate: Uzhhorod, Pittsburgh, (594,465), United States, Ukraine, Czech Republic
- Slovak Greek Catholic Church (1646): Prešov, (243,335), Slovak Republic, Canada
Other Churches sui iuris
Other than the above mentioned three forms of sui iuris churches there are some other sui iuris ecclesiastical communities. It is "a Church sui iuris which is neither patriarchal nor major archiepiscopal nor Metropolitan, and is entrusted to a hierarch who presides over it in accordance with the norm of common law and the particular law established by the Roman Pontiff" (CCEO. 174). The following churches are of this juridical status:
- Albanian Greek Catholic Church (1628) - apostolic administration: (3,510), Albania
- Belarusian Greek Catholic Church (1596) - no established hierarchy at present: (10,000), Belarus
- Bulgarian Greek Catholic Church (1861) - apostolic exarchate: Sofia,(10,107), Bulgaria
- Byzantine Church of the Eparchy of Križevci (1611) - an eparchy and an apostolic exarchate: Križevci, Ruski Krstur (21,480) + (22,653), Croatia, Serbia and Montenegro
- Greek Byzantine Catholic Church (1829) - two apostolic exarchates: Athens, (2,325), Greece, Turkey
- Hungarian Greek Catholic Church (1646) - an eparchy and an apostolic exarchate: Nyiregyháza, (290,000), Hungary
- Italo-Albanian Catholic Church (Never separated) - two eparchies and a territorial abbacy: (63,240), Italy
- Macedonian Greek Catholic Church (1918) - an apostolic exarchate: Skopje, (11,491), Republic of Macedonia
- Russian Catholic Church (1905) - two apostolic exarchates, at present with no published hierarchs: Russia, China; currently about 20 parishes and communities scattered around the world, including five in Russia itself, answering to bishops of other jurisdictions
- ↑ "Eastern Churches". Catholic Encyclopedia. New York: Robert Appleton Company. 1913. http://en.wikisource.org/wiki/Catholic_Encyclopedia_(1913)/Eastern_Churches.
- ↑ Church sui iuris
- ↑ For a better understanding of the concept of church sui iuris see, Žužek, Understanding The Eastern Code, pp. 103-104.
- This article incorporates text from the Encyclopædia Britannica, Eleventh Edition, a publication now in the public domain.
- Papal Address to Bishops of Central Asia - 23 September 2001
- Catholic MissionCatholic Churches in Turks and Caicos Islands
- An overview of the sui iuris status according to the Syro-Malankara Catholic Church
- Article distinguishing between unity and uniformity, from Kottayam Catholic Diocese
- Syro Malankara Catholic Church International Homepagecs:Sui iurispt:Igreja particular sui juris