Dear Clement:

This can be a confusing subject. Perhaps I can clear it up a bit.

There are two kinds of Eastern Christian Churches. One is the Orthodox Churches (they are not Orthodox Catholics). The Orthodox Churches split from the Catholic Church several times actually, but permanently in the 11th century.

Some of the Eastern Christians remained with the Catholic Church and others returned to the Catholic Church later. These form the Eastern Catholic Churches or "Rites."

For example, the Byzantine Catholic Church is the Greek Eastern Church that is in communion with Rome. The Greek Orthodox Church belongs to the group of Orthodox Churches that split from Rome.

"In communion with Rome" means that they accept and are in union with the authority and primacy of the Pope and are in communion with Catholic teaching.

The Orthodox Churches do not accept the authority of the Pope and reject some teachings of the Catholic Church. They accept only the first seven ecumenical councils. Thus, they reject the ecumenical councils that defined, for example, the dogmas on the Pope and papal infallibility, the Immaculate Conception and the Assumption of Mary.

The Catholic Church has six major "Rites" and various other "subgroups" within those Rites. A "rite" refers to a liturgical tradition. The largest rite is the Roman Rite which is a subgroup of the Latin Church.

The various Rites of the Catholic Church is the major factor that makes the Catholic Church catholic (universal). No other church or ecclesial fellowship can claim true universality.

The six primary liturgical traditions and their subgroups are:

Western (Latin) Church

1. Roman Church
   
   The Roman Rite is further divided into the following:
      a) Ordinary Form (Roman Missal 2000) - Vatican II
      b) Extraordinary Form (Roman Missal 1962) - Tridentine
      c) Ordinariate Use: The three primary Anglophone Ordinariates are:
          1) Our Lady of Walsingham (England and Wales, Scotland),
          2) Our Lady of the Southern Cross (Australia, Japan),
          3) Chair of St. Peter (United States, Canada)
      d) Algonquian and Iroquoian Uses (17th Century to Vatican II, rarely since then)
      e) Zaire Use (very limited extent in some African countries since the late 1970s)
   
   Gallican Type: Ambrosian, Braga, Mozarabic, Carthusian
   
   Sui Generis Type: Benedictine
   
   [the Dominican, Carmelite and Carthusian have now adopted the Roman Rite]
   
   

Eastern Churches

2. Byzantine Church
   14 sub-groups: Albanian, Bulgarian, Byelorussian, Georgian, Greek, Italo-Albanian, Melkite, Hungarian, Russian, Ruthenian, Romanian, Ukrainian, Yugoslav, Slovak

3. Alexandrian Church
   4 sub-groups: Eritrean, Ethiopian, Coptic (Egypt), Ethiopian (Abyssinian)

4. Antichene Church
   East Syrian:Chaldian (Middle East, Europe, Africa, and Americas) and Syro-Malabarese (India)
   
   West Syrian: Malankarese (India), Maronite (worldwide, but mainly in Lebanon), Syrian (Syria, Lebanon, Iran, Egypt, Turkey)
   
   
5. Armenian Church (Near East, Middle East, Europe, Africa, Americas, Australia)
   
   
6. Malabar Church (Southwest India)

All these are Catholic Churches. The Orthodox Churches, some of which have similar names, are not Catholic Churches.

The bottomline is that the Eastern Churches are national or ethnic Churches. Some of these ethnic peoples are in communion with Rome and some are not. (e.g., Greek Orthodox are not in communion while the Catholic Greeks [called Byzantine] are in communion).

Clear as mud? :)

God Bless,
Bro. Ignatius Mary