A Matter of "Rites"
Roman and Eastern Catholic Churches
Did you know that Catholic priests can get married? And that in the Catholic church, we have archpriests, Patriarchs, and eparchies? What is all of this?
Well these are terms related to the Eastern Rites of the Catholic Church. There are about a half dozen major groups of Rites other than the Roman Rite in the Catholic Church. In other words, not every Catholic is a "Roman Catholic.
In the Eastern Catholic Churches, priests can be married, but generally bishops are selected only from the Monastic or celibate priests. Most of the Eastern Rites have corresponding branches in the Orthodox church. Historically, the Eastern and Western churches separated in the Great Schism of 1054, mainly because of disputes over governance of the church rather than church doctrine. We have yet to repair the break that occurred at that time and which continues to bring pain to the people of God.
Anyway, the East and West separated, but some groups of the East wanted to have union with the Pope and still keep their Eastern traditions, including long solemn liturgies in Greek, strong use of icons, and a very mystical spirituality.
Those churches which have kept their Eastern roots and traditions, but are part of the single Catholic Church under the Pope, are called Catholics of the Eastern Rite. These churches are in full communion of faith with the Roman Rite, and accept the authority of the Pope. They keep their customs, traditional devotions, the optional celibacy for priests, and their own specific liturgical traditions.
One of my seminary professors used to remind us Roman Catholic Seminarians that the Roman Rite is the 800-pound gorilla in the church. Because the Roman Rite is the largest and most vocal, many Roman Catholics trample over the traditions and prerogatives of our fellow Catholics of the Eastern churches. What we need is greater respect and better acknowledgement of the Eastern Rites, and recognition of the contribution they make to the church as a whole.
In closing, all Catholics can attend the Divine Liturgy or the Holy Sacrifice of the Mass and receive communion in all Eastern or Western Catholic churches. Eastern churches often deliver communion by means of a spoon, and use consecrated leavened bread soaked in consecrated wine for the Eucharist, so be prepared. Right now, if the church says "Orthodox or "Polish National Catholic, be aware that those churches are not in communion with the Pope, and so are not Catholic churches. Some Eastern Catholic churches you will find in the United States include the Maronite, Melkite, Armenian, Ukrainian, Ruthenian, Syrian, and Chaldean Churches, and some others too.