stylistic:style_transfer
Latin and Eastern churches

In the first thousand years of Catholic history, different varieties of Christianity developed in the Western and Eastern Christian areas of Europe, Asia and Africa. Though most Eastern-tradition churches are no longer in communion with the Catholic Church after the Great Schism of 1054 (as well as the earlier Nestorian Schism and Chalcedonian Schism), 23 autonomous particular churches of eastern traditions participate in the Catholic communion, also known as "churches sui iuris " (Latin: "of one's own right "). The largest and most well known is the Latin Church, the only Western-tradition church, with more than 1 billion members worldwide. Relatively small in terms of adherents compared to the Latin Church, are the 23 self-governing Eastern Catholic Churches with a combined membership of 17.3 million as of 2010.

The Latin Church is governed by the pope and diocesan bishops directly appointed by him. The pope exercises a direct patriarchal role over the Latin Church, which is considered to form the original and still major part of Western Christianity, a heritage of certain beliefs and customs originating in Europe and northwestern Africa, some of which are inherited by many Christian denominations that trace their origins to the Protestant Reformation.

The Eastern Catholic Churches follow the traditions and spirituality of Eastern Christianity and are churches that have always remained in full communion with the Catholic Church or who have chosen to re-enter full communion in the centuries following the East–West Schism or earlier divisions. These churches are communities of Catholic Christians whose forms of worship reflect distinct historical and cultural influences rather than differences in doctrine. The pope's recognition of Eastern Catholic Churches, though, has caused controversy in ecumenical relations with the Eastern Orthodox and other eastern churches. Historically, pressure to conform to the norms of the Western Christianity practised by the majority Latin Church led to a degree of encroachment (Liturgical Latinisation) on some of the Eastern Catholic traditions. The Second Vatican Council document, Orientalium Ecclesiarum, built on previous reforms to reaffirm the right of Eastern Catholics to maintain their distinct liturgical practices.

A church sui iuris is defined in the Code of Canons for the Eastern Churches as a "group of Christian faithful united by a hierarchy" that is recognized by the pope in his capacity as the supreme authority on matters of doctrine within the church. The Eastern Catholic Churches are in full communion with the pope, but have governance structures and liturgical traditions separate from that of the Latin Church. While the Latin Church's canons do not explicitly use the term, it is tacitly recognized as equivalent.

Some Eastern Catholic churches are governed by a patriarch who is elected by the synod of the bishops of that church, others are headed by a major archbishop, others are under a metropolitan, and others are organized as individual eparchies. Each church has authority over the particulars of its internal organization, liturgical rites, liturgical calendar and other aspects of its spirituality, subject only to the authority of the pope. The Roman Curia has a specific department, the Congregation for the Oriental Churches, to maintain relations with them. The pope does not generally appoint bishops or clergy in the Eastern Catholic Churches, deferring to their internal governance structures, but may intervene if he feels it necessary.