Most, although not all use bread with yeast. Armenian Apostolic and a few others do not use yeast bread.

Eastern Rite Catholics also use the same bread as the Eastern Orthodox Churches.

The interpretation of the Bible held in the East, is that the Last Supper took place on the Eve of the Passover, so unleavened bread was not required. The Latin Rite interpretation is that it was the Passover Meal, at which the Eucharist was instituted. Since the Church has not officially defined if it was one or the other, both are permitted by Church Law. The Laws of the Latin Rite state that only Unlevended bread is licit, (Legal) for use in the Eucharistic Celebrations of the Latin Rite. Eastern Rite Catholic Churches (and the Orthodox equivalents) have their own Canon and Liturgical Laws according to the Rite. The manner that they distribute Communion, (In many Eastern Liturgies, the priest puts the Consecrated bread into the chalice and administers both with a spoon.) In others, the priest administers the consecrated host, or consecrated bread which he inticts, or dips into the chalice.

One thing that each of us needs to realize is that the Eastern Rite Catholic Liturgies, as just as much the Mass as any Latin/Western Rite Catholic Liturgy. At every Mass, we stand at the foot of the Cross. At every Mass, Jesus is the primary priest, who is present for us, both in the Eucharits, and through His minister, the priest.

Another thing that I forgot at the time I posted the information about zyme and azyme, (Yeast and non yeast breads) is that prior to the Western Churches using only unleavened bread, both were used in West and East. The change over to only unleavened bread in the West came about later. While it was always held that both were valid for use in the Eucharist, it became a bone of contention amone some Orthodox later.

There are a number of things like the bread having or not having yeast that were picked at as differences, that became blown out of proportion after the 1054 Schism. Just like crazy accusations that it was the Catholic Church who “Sold Indulgences” rather than individuals like Tetzel who were later repremanded for doing something contrary to Catholic practice. Levening or not was a non-issue that became an issue only after the Schism.

The Western Church holds zyme and azyme to both be valid. In the west it is only licit, (Legal) to use unlevened bread, without special permission. If a priest used leavening in the bread, in the West it would be an illegal act against church law, but not God’s law, so the Eucharist would be present. The Eucharist confected by bread that has or does not have yeast is the same, it is Jesus’ Body and Blood. Each drop and crumb the same as the other. At no time after the consecration and before the bread stops having the appearence of bread is one host or portion of the yeast bread any less Jesus than any other consecrated bread.

If a Catholic marries in a non-catholic service, or by a Justice of the Peace they may not under normal circumstances receive communion until they have gone to confession and attempted to regularize the marriage.

The exceptions to the rule are that a bishop may for serious reason allow the person to marry in a non-catholic service, usually a Catholic priest present to wittness for the Church, the conditions may include that a Catholic service be held sometimes in private. In the UK the State requires that a person who is qualified preform a civil service, and then a Religious Service may take place. Most all Anglican Clergy are certified to preform the civil service, and usually do in either the rectory or the sacristy prior to the Church wedding. Select clergy of other Churches in the UK are also qualified to do so.

To stretch the answer out even further, the Church requires her subjects to follow both civil and Church law, in order that the State also recognize the marriage, even though it usually has different standards. So if the State requires a license, or civil ceremony, the Church allows it, as long as the Church service is also preformed.

It must be remembered that the priest does not really marry the people. What he does is wittnesses the marriage, offers the blessings of the Church, and assures that the marriage is conducted in a proper manner. If no priest can be obtained in a reasonable time, a marriage may take place between two people with two Catholic wittnesses, and is blessed when a priest is availible. This was more common when the US and other countries were mission terretories, and a priest only came through once or twice a year.

Armenian Apostolic are not in communion with Rome. However of all the Orthodox, (in my experience) the Armenian Apostolic are the least hostile tward Rome. One Armenian priest told me, that in Armenia, Orthodox and Catholics were fighting the same enemy, Communism, and in Lebanon, Iraq and Iran, they were fighting against Islam all the enemies were attacking Chrisitanity, so most Armenians forgot who you were in communion with, and focused on attending Mass, and having a priest administer the Sacraments, Catholic or Apostolic.

Now based on Canon Law, this was wrong, but based on the spiritual needs of the time and place it was a manifestation of God’s love for us all, Orthodox and Catholic.

Popes Paul VI, John Paul II and Benedict XVI have all met with the Patriarchs of Constantinople. It is a sign of progress. However you have to remember, the Patriarchs of Individual Orthodox Churches do not have any more authority than any other bishop in the Orthodox Church, they are the Ordinary Bishop of the See that is the Mother of each National Church (more or less) and while they are looked to for advice and leadership, they are one among many, and cannot make a unilateral decision.

We should all pray as Jesus did, that we may all be one.