In our Russian Church, we use five Prosphora loaves for the Proskomide [the Service of Preparation, or Prothesis, also called Proskomedia, and despite the clear derivation from the Greek, (“proskomizo”) or “to offer,” Prokimidi and Proskimidia]. In other traditions, they use one with five seals on it. Also, some use two layers for the loaf, others one. Can you explain this?
The use of more than one Prosphoron (plural, ta Prosphora) (loaf) for the celebration of the Eucharist is not the very ancient practice of the Church and departs from the Scriptural symbolism of the “one bread” in St. Paul’s commentary on the Divine Eucharist (1 Cor. 10:16-17). Nonetheless, early on in the liturgical texts we find references to a number of Prosphora, as in the fourteenth-century Diataxis of Patriarch Philotheos. St. Symeon of Thessaloniki (+1430), the noted liturgical expert, also describes the Proskomide service in some detail, noting that “one” of the loaves on the Table of Preparation is used for the initial blessing service (St. Symeon, Archbishop of Thessaloniki, Ta Apanta, Thessaloniki, 1983, p. 110) — though there is no indication that more than one loaf was actually used for the Eucharist. Nonetheless, the use of a number of loaves is part of what some scholars call a clear development from about the tenth century on. (See, for example, Father Lawrence Barriger, “The Legacy of Constantinople in the Russian Liturgical Tradition” [Greek Orthodox Theological Review, Vol. 33 (4), pp. 387-416], whose curious view of such things as the “Litany of the Catechumens” may, however, impugn his general expertise in Orthodox liturgical matters.) Others see this trend as the result of a possible confusion among less-educated clergy of the Proskomide with the blessing of the Five Loaves, or Artoklasia. On Mt. Athos, the Eucharist is usually celebrated with two Prosphora, the triangle honoring the Theotokos and the particles for the Saints and other commemorations coming from the second loaf.
As an interesting aside, we might note that, before the Fall of Constantinople, the Prosphoron, which is now round in form, was in the shape of a square. The seal in the middle of the square loaf was, however, round, marked with a Cross and the familiar symbol, “IC XC NIKA” (“Jesus Christ conquers”). This custom — i.e., the use of a square loaf (Artos, as he calls it) is also noted by St. Symeon of Thessaloniki (ibid., pp. 111-112).
The preparation of a single Prosphoron from two layers of leavened bread placed together is also an ancient custom. The two layers in one loaf represent the two natures of Christ. (Orthodox Insights vol. I, pp. 15-16)