Early Christianity and the patristic Tradition understood the Eucharist as the Sacrament of authentic and real communion with Christ. Speaking of the Eucharist, Chrysostom insisted that "Christ is now present and now active"492; and Gregory of Nyssa, in spite of his inclination to Platonism, expounds the same view of the Eucharist in a different way – as the sacrament of real "participation" in the glorified Body of Christ as the seed of immortality.

By the distribution of His mercy, He sows Himself in everyone who believes through the flesh, the transubstantiated bread and wine, uniting Himself with the bodies of believers. And by this union with the Eternal, man can also participate in immortality. He grants this by virtue of the blessing by which He transforms [metastoicheiosis] the natural quality of these visible things into that imperishable thing.

Participation in these sources of immortality and unity is a constant concern of every Christian:

It is good and beneficial to partake of Communion every day [writes Basil] and to partake of the Holy Body and Blood of Christ. For He says exactly: "He who eats My Flesh and drinks My Blood has eternal life" (John 6:55). And who can doubt that often participating in life is the same as having a full life? I commune four times a week, on the Lord's Days, Wednesdays, Fridays, and Saturdays, and on other days when a saint is commemorated.

As we have seen, this realistic and existential theology of the Eucharist came into conflict with the pastoral needs of the post-Constantinian Church: the gathering of large numbers of the faithful in large churches led to a decrease in the participation of the laity in the life of the community.

One can try to prove that the pastoral considerations behind such a development can be justified, at least in part; the eschatological meaning of the Eucharist implied the separation from the "world", the "withdrawal" from it of the "closed" community of consecrated participants. And now, when in the empire of Constantine and Justinian it had become difficult to distinguish between the Church and the world, because society seemed to be one, the Eucharist had to be guarded from the "crowd," which had ceased to be "the people of God." Most controversial, however, is the theological justification for this new situation preached by some interpreters of the Liturgy, who have begun to explain the Eucharist as a system of symbols to be "contemplated"; sacramental participation was thus gradually replaced by speculation. Needless to say, such a new approach fit perfectly into the Origenist and Evagrian understanding of religion as the ascent of reason to God, and the liturgical act is only a symbol of such an ascent.

The most effective instrument for the dissemination of such a symbolic understanding of the Eucharist was the writings of Pseudo-Dionysius. Reducing the Eucharistic "synaxis"496 to the level of a moralistic proclamation, the Areopagite calls its readers to a "higher" contemplation:

Let us leave these imperfect signs, which, as I have said, are excellently depicted in the vestibules of sanctuaries; there will be enough of them to be nourished by their contemplation. If we are so anxious, let us turn back to the consideration of holy communion, from their effects to their causes, and, thanks to the light which Jesus bestows upon us, we shall be able to contemplate harmoniously the intelligible realities in which the sanctified goodness of the patterns is clearly reflected.

Thus, the Eucharist is only a visible "consequence" of an invisible "model"; and he who performs the Sacrament, "offering Jesus Christ to our eyes, shows us in a tangible way and as if in a certain image, our intelligible life" (498). Therefore, for Dionysius, "the most sublime meaning of the Eucharistic rites and communion in the Sacrament itself consists in the signification of the union of our minds with God and with Christ. … Dionysius never formally presents Eucharistic communion as the transmutation of the Body and Blood of Christ.

Dionysius' symbolism only superficially influenced the Eucharist as such, but it gained great popularity among interpreters of the Liturgy. Thus, the great Maximus the Confessor, who interpreted the concept of "symbol" more realistically than Dionysius, nevertheless consistently uses the terms "symbol" and "image" in relation to the Eucharistic liturgy in general and to such elements of it as bread and wine, in particular.

In the eighth century, this symbolism led to a serious theological controversy over the Eucharist, the only controversy on this subject that Byzantium had ever known. The Iconoclastic Council of 754, condemning the use of religious images, proclaimed that the only permissible "image" of Christ was that which had been established by Christ Himself, the Eucharistic Body and Blood. Such a radical and clear statement was a real challenge to Orthodoxy, and it once again confirmed the ambiguity of the Areopagite and symbolism in general.

Therefore, the defenders of the images, especially Theodore the Studite and Patriarch Nicephorus, resolutely rejected this claim of the council. For Theodore, the Eucharist is not a type, but truth itself; it is the mystery that restores the fullness of [divine] Providence" (502). According to Nicephorus, it is the very "flesh of God," "one and the same thing" with the Body and Blood of Christ,503 who came to save the very reality of man's flesh, and who became and remained "flesh," even after His glorification; therefore, in the Eucharist, "what then is the subject of the sacrament, if the flesh is not real? What, then, do we see the Spirit doing?" 504.

As a result of the iconoclastic strife, Byzantine "Eucharistic realism", clearly separated from the terminology of Dionysius, received a new direction and began to be expounded in the mainstream of Christological and soteriological problems; in the Eucharist, man participates in the glorified humanity of Christ, which is not the "essence of God",505 but a humanity still consubstantial with man and accessible to him as food and drink. In his treatise Against Eusebius and Epiphanius, Patriarch Nicephorus particularly denounces the Origenist idea that in the Eucharist man contemplates or participates in the "essence" of God. For him, as for the later Byzantine theologians, the Eucharist is Christ's transfigured, life-giving, but still human body, hypostasized in the Logos and permeated with divine "energies." It is noteworthy that among Byzantine theologians it is impossible to find a case of the use of the term "essence" (ousia) in a Eucharistic context. And terms such as "transubstantiation" (metousiçsis) were considered inappropriate for the sacrament of the Eucharist, and were usually used to use the concept of metabole 507 found in the canon of John Chrysostom, or such dynamic terms as "re-conception" (metastoichei?sis) or "re-appointment" (metarrhythmisis). Transubstantiation (metousiñsis) appears only in the works of the Latinophrones ("Latin-minded") of the thirteenth century, and this term is nothing more than a direct translation from Latin. The first Orthodox author to use the word was Gennadius Scholarius, but even in his case the direct Latin influence is evident. The Eucharist is not a sign to be "beheld" from without, nor is it an "essence" distinct from humanity, but it is Jesus Himself, the Risen Lord, who "was known... in the breaking of bread" (Luke 24:35); Byzantine theologians seldom went beyond such a realistic and soteriological affirmation of the Eucharistic presence as the presence of the glorified humanity of Christ.

The rejection of the understanding of the Eucharist as an "image" or "symbol" is, on the other hand, very important for the understanding of the entire "perception" of the Eucharist by the Byzantines; for them, the Eucharist always remained a mystery that had to be taken as food and drink and which could not be "seen" with the bodily eyes. These aspects have always remained hidden, except during the recitation of the prayer of consecration and Communion; and, in contrast to Western medieval piety, they were never "venerated" except within the framework of the Eucharistic liturgy proper. The Eucharist could not reveal anything to the mind's eye; it is only the Bread of Heaven. The eye was offered another means of revelation – icons: hence the discovery of the plan of the Byzantine iconostasis with the figures of Christ and the saints, exhibited precisely to be seen and venerated. "Christ is not shown in the Holy Gifts," writes Leonid Uspensky, "He is given in them. He is shown in icons. The visible side of the reality of the Eucharist is an image that cannot be replaced by imagination or contemplation of the Holy Gifts."509