For nearly a thousand years, Greek and Latin Christians accused each other over a loaf of bread. Was the bread ever the real problem?
Short answer: No. Christ becomes truly present in the Eucharist in wheat bread whether it is leavened or unleavened. The Catholic Church defined this at the Council of Florence in 1439, with Greek bishops agreeing: "the body of Christ is truly confected in both unleavened and leavened wheat bread." Today Latin Catholics use unleavened bread and most Eastern Catholics use leavened bread, at the same altar of faith, in one Catholic Church. What makes the Eucharist is Christ's word spoken by a validly ordained priest, not the leaven. The azymes dispute was never a real reason to stay apart.
Key verses on the Eucharistic bread
- "Then he took the bread, said the blessing, broke it, and gave it to them, saying, 'This is my body, which will be given for you; do this in memory of me.'" (Luke 22:19)
- "On the first day of the Feast of Unleavened Bread, when they sacrificed the Passover lamb" (Mark 14:12)
- "For our paschal lamb, Christ, has been sacrificed." (1 Corinthians 5:7)
- "The kingdom of heaven is like yeast that a woman took and mixed with three measures of wheat flour until the whole batch was leavened." (Matthew 13:33)
- "I am the living bread that came down from heaven; whoever eats this bread will live forever; and the bread that I will give is my flesh for the life of the world." (John 6:51)
Scripture quotations are from the New American Bible, Revised Edition (NABRE), © 2010, 1991, 1986, 1970 Confraternity of Christian Doctrine, Washington, D.C. Used by permission. All rights reserved.
What the Orthodox Believe
The Orthodox Church uses leavened bread (in Greek, prosphora for the loaves offered, from which the Lamb is cut). The Orthodox Church in America explains: "Actually, leavened bread has always been used in the Eastern Church." It adds that "In the Christian East there is no concern for using the exact type of bread used at the Last Supper," because "the purpose of the Eucharistic celebration is not to 'recreate' or 'reproduce' a past event" but "to participate in an event that is beyond time and space."
Orthodox writers give deeper reasons too. An Orthodox Q&A published by the Catalog of Good Deeds calls leavened bread "the ancient apostolic practice," says unleavened use "dates to the 8th century," and argues that the Gospel word for the bread, artos, "generally means regular bread." Leaven is often a symbol of sin in Scripture, it admits, but here it "was understood as symbolic of life," pointing to "the living and risen body of Christ." It also holds that "St. John's chronology should be seen as a clarification": if the Last Supper came before Passover, ordinary leavened bread would have been on the table. St. John the Evangelist Orthodox Church (Beaver Falls, PA) adds that "the Kingdom spreads like yeast" and that unleavened bread "is connected with mourning."
In the eleventh century the argument was sharper. In 1053 Patriarch Michael Cerularius closed the Latin churches in Constantinople, and his close ally Leo, archbishop of Ohrid (metropolitan of the Bulgarians), wrote to Bishop John of Trani in southern Italy attacking the Latin use of unleavened bread (azymes), together with Latin Sabbath observances, as Jewish practices instituted by Moses. Leo contrasted leavened bread, which rises with life, with unleavened bread, which he called lifeless. Cerularius went further and denied that an unleavened offering was a valid Mass at all (Catholic Encyclopedia, "Azymites"). The azymes became one of the flash points of the mutual excommunications of 1054 (see What Caused the Great Schism of 1054?).
What Catholics Actually Teach
The Catholic Church teaches that "The essential signs of the Eucharistic sacrament are wheat bread and grape wine, on which the blessing of the Holy Spirit is invoked and the priest pronounces the words of consecration spoken by Jesus during the Last Supper" (CCC 1412). Notice what is essential: wheat bread, grape wine, the Holy Spirit, and Christ's words. Leaven is not on the list.
The Council of Florence, in its decree of union with the Greeks (Laetentur caeli, July 6, 1439), defined: "Also, the body of Christ is truly confected in both unleavened and leavened wheat bread, and priests should confect the body of Christ in either, that is, each priest according to the custom of his western or eastern church" (Council of Florence, Session 6, EWTN text of the decree). The same decree also defined that "the holy apostolic see and the Roman pontiff holds the primacy over the whole world." Florence settled the bread in one sentence; the question that actually divides is communion with St. Peter's successor.
Latin law follows Florence. "According to the ancient tradition of the Latin Church, the priest is to use unleavened bread in the eucharistic celebration whenever he offers it" (canon 926). The bread "must be only wheat" (canon 924 §2). Meanwhile Byzantine Catholics, in full communion with the pope, use leavened bread. As Catholic Answers puts it, "Eastern-rite churches in communion with Rome are allowed to retain their own tradition of using leavened bread" (see Are Eastern Catholic Churches Really Catholic?).
What makes the bread become Christ's Body? Not the baker. "Only validly ordained priests can preside at the Eucharist and consecrate the bread and the wine so that they become the Body and Blood of the Lord" (CCC 1411). And the Catechism quotes a Father the Orthodox love, St. John Chrysostom: "It is not man that causes the things offered to become the Body and Blood of Christ, but he who was crucified for us, Christ himself.... This is my body, he says. This word transforms the things offered" (CCC 1375).
What Catholics do not teach:
- That leavened bread is invalid. Florence said the opposite, and Byzantine Catholic priests consecrate leavened bread every Sunday.
- That the Orthodox Eucharist is false. "The Eastern churches that are not in full communion with the Catholic Church celebrate the Eucharist with great love" (CCC 1399). Their Eucharist is true, yet it is celebrated apart from St. Peter's successor, and such gifts "are in themselves calls to 'Catholic unity'" (CCC 819).
- That a priest may pick either bread as he likes. Each priest follows his own Church's custom. St. Thomas Aquinas, though he preferred the Latin usage, granted that the Greek custom "is not unreasonable" and that "it is suitable that every priest observe the rite of his Church in the celebration of the sacrament" (Summa Theologiae III, q. 74, a. 4).
It all points to Christ. Both loaves preach the same Lord. Unleavened bread recalls the "unleavened bread of sincerity and truth" (1 Corinthians 5:8) and the Passover Christ fulfilled; leavened bread recalls the risen Christ who leavens the whole world (Matthew 13:33). Neither loaf is the point. Jesus is the point: the sacraments "are efficacious because in them Christ himself is at work" (CCC 1127), and He says over both, "This is my body."
The Biblical Case
1. Christ's words make the Eucharist, not the leaven
Every account of the institution centers on what Jesus said and commanded: "Take and eat; this is my body" (Matthew 26:26); "Take it; this is my body" (Mark 14:22); "This is my body, which will be given for you; do this in memory of me" (Luke 22:19). St. Paul hands on the same: "the Lord Jesus, on the night he was handed over, took bread, and, after he had given thanks, broke it and said, 'This is my body that is for you. Do this in remembrance of me'" (1 Corinthians 11:23–24). None of these four texts says whether the loaf was leavened. The weight falls on the Lord's word and His command, "Do this." A Church that has Christ's word and a true priesthood has the Eucharist.
2. The Synoptic Gospels place the Last Supper at Passover
Three Gospels date the meal to the feast of unleavened bread. "On the first day of the Feast of Unleavened Bread, the disciples approached Jesus and said, 'Where do you want us to prepare for you to eat the Passover?'" (Matthew 26:17). St. Mark adds, "when they sacrificed the Passover lamb" (Mark 14:12). St. Luke: "When the day of the feast of Unleavened Bread arrived, the day for sacrificing the Passover lamb" (Luke 22:7), and Jesus said, "I have eagerly desired to eat this Passover with you before I suffer" (Luke 22:15). That week the Law required: "From the very first day you will have your houses clear of all leaven" (Exodus 12:15). Read plainly, the Synoptics give the Latin usage strong biblical footing.
3. St. John's chronology must be heard too
St. John's Gospel times things differently. On Good Friday morning the leaders would not enter the praetorium "in order not to be defiled so that they could eat the Passover" (John 18:28), and Jesus was sentenced on "preparation day for Passover, and it was about noon" (John 19:14). The NABRE note itself says: "the synoptic gospels give the impression that the Thursday night supper was the Passover meal (Mk 14:12); for John that meal is still to be eaten Friday night." Another note observes that noon was "the hour at which the priests began to slaughter Passover lambs in the temple." Scholars still debate how to reconcile the two timelines. If St. John's dating is taken strictly, the Lord may have used ordinary bread; if the Synoptics' dating is taken strictly, He used unleavened bread. Scripture does not settle it beyond dispute, and that is exactly why the bread cannot be a church-dividing doctrine: what Scripture leaves open, no one may make a condition of communion.
4. Scripture uses both images of Christ
The Bible gives each side a beautiful image. For the Latin usage: "Clear out the old yeast, so that you may become a fresh batch of dough, inasmuch as you are unleavened. For our paschal lamb, Christ, has been sacrificed. Therefore let us celebrate the feast, not with the old yeast, the yeast of malice and wickedness, but with the unleavened bread of sincerity and truth" (1 Corinthians 5:6–8). For the Eastern usage: "The kingdom of heaven is like yeast that a woman took and mixed with three measures of wheat flour until the whole batch was leavened" (Matthew 13:33). Both are inspired. Neither is a command about Eucharistic bread. Calling one loaf "dead" and the other "living" makes a symbol do what only Christ does: "I am the living bread that came down from heaven" (John 6:51). The life is in Him, not in the yeast.
5. The one bread is meant to make one body
St. Paul teaches that the one bread makes one body (1 Corinthians 10:16–17). A dispute about the bread that keeps the body divided turns the sacrament of unity against its own purpose.
Objections Answered
(a) "Unleavened bread is lifeless. Leaven signifies the soul and the risen Christ."
At its strongest: Leo of Ohrid argued that leavened bread has life and unleavened bread is lifeless; the risen, living Christ should be offered in risen bread. Modern Orthodox writers say leaven "was understood as symbolic of life," pointing to "the living and risen body of Christ."
Answer: The symbolism of leaven is a fair meditation, and the Catholic Church honors it: Byzantine Catholics use leavened bread to this day. But a symbol cannot become a test of validity. Scripture uses leaven for the kingdom (Matthew 13:33) and also for "malice and wickedness" (1 Corinthians 5:8). After the consecration, no bread remains at all: the Church teaches that "by the consecration of the bread and wine there takes place a change of the whole substance of the bread" into the substance of Christ's Body (CCC 1376, quoting Trent; see Is the Eucharist Really the Body and Blood of Jesus?), and the Orthodox, too, confess a real change. Whatever the loaf was, it is now the living Christ. Nothing "lifeless" lies on any altar where a true priest has said, "This is my body."
(b) "Unleavened bread is Judaizing. Christians do not keep Mosaic feasts."
At its strongest: St. Ignatius warned, "Lay aside, therefore, the evil, the old, the sour leaven, and be changed into the new leaven, which is Jesus Christ," and in the same chapter, "Christianity did not embrace Judaism, but Judaism Christianity" (Magnesians 10). Azymes belong to the Law; the new covenant should leave them behind.
Answer: St. Ignatius's point is moral and doctrinal: Christians must not live by the old Law. He says nothing about Eucharistic bread, and his "old, sour leaven" is the same image as St. Paul's, where Christians are told to be "unleavened" (1 Corinthians 5:7). The Latin Church uses unleavened bread not as a Mosaic observance but because the Gospels place the Last Supper at Passover, when "they sacrificed the Passover lamb" (Mark 14:12). The Orthodox themselves keep Old Testament elements fulfilled in Christ: altar, incense, the Psalms. Fulfillment is not Judaizing.
(c) "The East has always used leavened bread; Rome changed."
At its strongest: Orthodox writers say leavened bread is apostolic and date Latin unleavened usage to the 8th century or later. Liturgical novelty is suspect.
Answer: Concede what is true: the evidence for the earliest centuries is thin. The Catholic Encyclopedia itself says our knowledge of the primitive Church's usage is so scant that many theologians have judged the question unsolvable, and that unleavened bread had become universal and obligatory in the West by the ninth century ("Azymites"). Even the Orthodox Q&A quoted above grants, citing the Catholic Encyclopedia, that history does not settle which bread the Apostles used. But a disputed historical question cuts both ways: it cannot prove the Latin Church abandoned an apostolic law, because no apostolic law about leaven exists in Scripture or the Fathers. Florence wisely honored both customs.
(d) "If it never mattered, why did the bread split East and West in 1054, and why did Florence fail?"
At its strongest: Orthodox writers present Patriarch Michael Cerularius as reacting, not attacking: "the Roman see approved the use of Latin customs among the Norman Christians," and "Michael reacted by directing the Latin churches in Constantinople to use Eastern usages" (OrthodoxWiki). When they refused, he closed them (Encyclopaedia Britannica). And Florence's union was rejected in the East.
Answer: Churchmen on both sides sinned in the eleventh century; Catholics should admit it. But Rome never demanded that Greeks give up leavened bread. The Catholic Encyclopedia calls the closing of the Latin churches "entirely unprovoked," and Pope St. Leo IX answered that "no one thought of attacking the many Byzantine monasteries and churches in the West" (Catholic Encyclopedia, "Michael Caerularius"). But the question is what the Catholic Church teaches, and she settled it: both breads are valid, and each Church keeps its custom. Byzantine Catholics have lived that decision for centuries. Florence did not fail on the bread. It failed in its reception: opponents such as Mark of Ephesus, whom the Orthodox venerate as a saint, pressed the filioque, purgatory, and the papacy, and deep popular distrust of the Latins did the rest. That is precisely our point: when the bread is removed as an objection, the questions that remain are doctrinal, and at their center is communion with St. Peter's successor.
The Early Church Agrees
Here is the honest truth: the earliest Fathers do not tell us whether the Eucharistic loaf was leavened. What they tell us, again and again, is what makes it the Eucharist: the invocation of God and Christ's own word. That is the Catholic answer to the azymes dispute.
- St. Ignatius of Antioch (Letter to the Magnesians 10, c. AD 107): "be changed into the new leaven, which is Jesus Christ" (newadvent.org). A spiritual image, like St. Paul's, not a rule about altar bread.
- St. Justin Martyr (First Apology 66, c. AD 155): "For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh" (ccel.org). The change comes from "the prayer of His word."
- St. Irenaeus of Lyons (Against Heresies 4.18.5, c. AD 180): "For as the bread, which is produced from the earth, when it receives the invocation of God, is no longer common bread, but the Eucharist, consisting of two realities, earthly and heavenly; so also our bodies, when they receive the Eucharist, are no longer corruptible, having the hope of the resurrection to eternity" (newadvent.org). Bread "produced from the earth" plus "the invocation of God."
- St. Ambrose of Milan (On the Mysteries 9.52, c. AD 387–390): "For that sacrament which you receive is made what it is by the word of Christ. But if the word of Elijah had such power as to bring down fire from heaven, shall not the word of Christ have power to change the nature of the elements?" (newadvent.org).
- St. John Chrysostom (late 4th century, quoted in CCC 1375), whose name the Divine Liturgy most often celebrated by the Orthodox bears: "This is my body, he says. This word transforms the things offered."
The Fathers agree: Christ's word makes the Eucharist. None made leaven a test of the Church.
Conclusion
The azymes controversy was real, but it was never a real reason for separation. Scripture does not command a kind of loaf; it commands, "Do this in memory of me." The Fathers locate the miracle in Christ's word, not the yeast. And the Catholic Church has settled the question for nearly six centuries: both breads are valid, and each Church keeps her own custom. A Ukrainian Catholic and a Roman Catholic receive different loaves and the same Christ, in the same Catholic Church.
So take the bread off the table as an objection. What is left is the question Florence placed beside it: communion with St. Peter's successor.
Come home. In the Catholic Church your leavened bread, your Divine Liturgy, and your whole tradition are already at home, as Byzantine Catholics prove every Sunday. You already possess true sacraments and much of the apostolic faith, in "a certain, although imperfect, communion with the Catholic Church" (CCC 838). Those gifts draw their power "from the fullness of grace and truth that Christ has entrusted to the Catholic Church" and "are in themselves calls to 'Catholic unity'" (CCC 819). The Eucharist is the sacrament of the Church's unity, yet your true Eucharist is celebrated apart from the successor of St. Peter, on whom Christ built His Church (Matthew 16:18). We invite you into full communion with St. Peter's successor, the bishop of Rome, in the Catholic Church.
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FAQ
Is a Mass with unleavened bread valid in Orthodox eyes? Orthodox opinion has varied. Cerularius and some Byzantine polemicists denied it; many Orthodox today, like the OCA answer quoted above, simply explain their own tradition without ruling on the West's. The Catholic Church's position is clear and was accepted by the Greek delegates at Florence (Mark of Ephesus refused to sign): "the body of Christ is truly confected in both unleavened and leavened wheat bread." What is required: wheat bread, grape wine, a valid priest, and Christ's words (CCC 1411–1412).
Do Eastern Catholics really use leavened bread? Yes. Byzantine Catholic Churches (for example, Ukrainian, Ruthenian and Melkite Catholics) keep their tradition of leavened bread in full communion with the pope. See Are Eastern Catholic Churches Really Catholic?
Can an Orthodox Christian receive Communion at a Catholic Mass? The Church's law permits Catholic ministers to give the Eucharist to "members of Eastern Churches which do not have full communion with the Catholic Church if they seek such on their own accord and are properly disposed" (canon 844 §3), though the Orthodox Churches themselves generally ask their faithful not to receive Communion outside their own Church, and Catholics should respect that. The goal is not occasional sharing but full communion. See Can Catholics Receive Communion in an Orthodox Church?
Sources
Scripture (NABRE, bible.usccb.org): Exodus 12:15; Matthew 13:33; Matthew 16:18; Matthew 26:17, 26; Mark 14:12, 22; Luke 22:7, 15, 19; John 6:51; John 18:28 and note; John 19:14 and note; 1 Corinthians 5:6–8; 1 Corinthians 10:16–17; 1 Corinthians 11:23–24.
Catechism of the Catholic Church (vatican.va): 819, 838; 1127; 1375, 1376; 1399; 1411, 1412.
Church documents: Council of Florence, Session 6, Laetentur caeli (July 6, 1439), ewtn.com; Code of Canon Law, cann. 924, 926; can. 844; St. Thomas Aquinas, Summa Theologiae III, q. 74, a. 4; Catholic Answers, "Eastern-rite Catholics use leavened bread...".
Church Fathers: Ignatius of Antioch, Magnesians 10; Justin Martyr, First Apology 66 (ANF vol. 1); Irenaeus, Against Heresies 4.18.5; Ambrose, On the Mysteries 9.52; John Chrysostom in CCC 1375.
Orthodox sources: Orthodox Church in America, "Leavened bread vs. unleavened"; Catalog of Good Deeds, "Why Do Orthodox Christians Use Leavened Bread?"; St. John the Evangelist Orthodox Church, "Why Do Orthodox Churches Use Leavened Bread For Communion?".
History: James Loughlin, "Azymites," Catholic Encyclopedia (1907), newadvent.org; Catholic Encyclopedia, "Michael Caerularius"; OrthodoxWiki, "Michael I Cerularius of Constantinople"; Encyclopaedia Britannica, "Michael Cerularius".