Uniatization

The Eastern Catholic Churches or Oriental Catholic Churches, also called the Eastern-rite Catholic Churches, and in some historical cases Uniate Churches, are twenty-three Eastern Christian particular churches sui iuris in full communion with the Pope in Rome, as part of the worldwide Catholic Church. Headed by patriarchs, metropolitans, and major archbishops, the Eastern Catholic Churches are governed in accordance with the Code of Canons of the Eastern Churches, although each church also has its own canons and laws on top of this, and the preservation of their own traditions is explicitly encouraged. The total membership of the various churches accounts for about 16 million, according to the Annuario Pontificio (the annual directory of the Catholic Church), thus making up about 1.5 percent of the Catholic Church, with the rest of its more than 1.2 billion members belonging to the (Western) Latin Church.

The Maronite Church is considered the only one of the Eastern Catholic Churches to have always remained in full communion with the Holy See, while most of the other churches unified from the 16th century onwards. However, the Melkite Catholic Church and the Italo-Albanian Greek Catholic Church also claim perpetual communion.

Full communion constitutes mutual sacramental sharing between the Eastern Catholic Churches and the Latin Church, including Eucharistic intercommunion. On the other hand, the liturgical traditions of the 23 Eastern Catholic churches, including Byzantine, Alexandrian, Armenian, East Syriac, and West Syriac, are shared with other Eastern Christian churches: the Eastern Orthodox, Oriental Orthodox, the Assyrian Church of the East, and the Ancient Church of the East. Although some theological issues divide the Eastern Catholic churches from other Eastern Christian ones, they do admit members of the latter to the Eucharist and the other sacraments, as governed by Oriental canon law.

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