Although the Great Schism is generally dated as happening in 1054, the truth is that the East and West had been at odds for some time. Yet, the Orthodox belief in the Real Presence is IDENTICAL to what Catholics believe.
Within decades of the Resurrection, St. Ignatius and others denounced those who denied the Real Presence as heretics; after that, NOBODY who claimed to be a Christian denied the Real Presence for another 13 or 14 centuries until Zwingli came along.
From the following message board, a lot of great information...
Augustine (354-430): In a word, He now explains how that which He speaks of comes to pass, and what it is to eat His body and to drink His blood. "He that eateth my flesh, and drinketh my blood, dwelleth in me, and I in him." This it is, therefore, for a man to eat that meat and to drink that drink, to dwell in Christ, and to have Christ dwelling in him. Consequently, he that dwelleth not in Christ, and in whom Christ dwelleth not, doubtless neither eateth His flesh [spiritually] nor drinketh His blood [although he may press the sacrament of the body and blood of Christ carnally and visibly with his teeth], but rather doth he eat and drink the sacrament of so great a thing to his own judgment, because he, being unclean, has presumed to come to the sacraments of Christ, which no man taketh worthily except he that is pure: of such it is said, "Blessed are the pure in heart, for they shall see God." NPNF1: Vol. VII, Tractates on John, Tractate 26, John 6:41-59, §18. Augustine (354-430): Let them come to the church and hear where Christ is, and take Him. They may hear it from us, they may hear it from the gospel. He was slain by their forefathers, He was buried, He rose again, He was recognized by the disciples, He ascended before their eyes into heaven, and there sitteth at the right hand of the Father; and He who was judged is yet to come as Judge of all: let them hear, and hold fast. Do they reply, How shall I take hold of the absent? how shall I stretch up my hand into heaven, and take hold of one who is sitting there? Stretch up thy faith, and thou hast got hold. Thy forefathers held by the flesh, hold thou with the heart; for the absent Christ is also present. But for His presence, we ourselves were unable to hold Him. NPNF1: Vol. VII, Tractates on John, Tractate 50, John 11:55-57, 12:1-11, §4. And elsewhere... Augustine (354-430): It seemed unto them hard that He said, "Except ye eat the flesh of the Son of Man, ye have no life in you:" they received it foolishly, they thought of it carnally, and imagined that the Lord would cut off parts from His body, and give unto them; and they said, "This is a hard saying." It was they who were hard, not the saying; for unless they had been hard, and not meek, they would have said unto themselves, He saith not this without reason, but there must be some latent mystery herein. They would have remained with Him, softened, not hard: and would have learnt that from Him which they who remained, when the others departed, learnt. For when twelve disciples had remained with Him, on their departure, these remaining followers suggested to Him, as if in grief for the death of the former, that they were offended by His words, and turned back. But He instructed them, and saith unto them, "It is the Spirit that quickeneth, but the flesh profiteth nothing; the words that I have spoken unto you, they are spirit, and they are life." Understand spiritually what I have said; ye are not to eat this body which ye see; nor to drink that blood which they who will crucify Me shall pour forth. I have commended unto you a certain mystery; spiritually understood, it will quicken. Although it is needful that this be visibly celebrated, yet it must be spiritually understood. NPNF1: Vol. VIII, St. Augustin on the Psalms, Psalm 99 (98), §8. But the most interesting quote to me as far as it concerns the contention of Roman Catholics is the denial of Pope Gelasius I of the concept of transubstantiation... Gelasius, Bishop of Rome (492-496): Surely the sacrament we take of the Lord´s body and blood is a divine thing, on account of which, and by the same we are made partakers of the divine nature; and yet the substance of the bread and wine does not cease to be. And certainly the image and similitude of Christ´s body and blood are celebrated in the action of the mysteries. (Tractatus de duabus naturis 14 [PL Sup.-III. 773]) See Francis Turretin, Institutes of Elenctic Theology, 3 Vols., trans. George Musgrave Giger and ed. James T. Dennison (Phillipsburg: reprinted by Presbyterian and Reformed Publishing Co., 1992), Vol. 3, p. 479 (XVIII.xxvi.xx). Latin text: Certe sacramenta, quae sumimus, corporis et sanguinis Christi divina res est, propter quod et per eadem divinae efficimur consortes naturae; et tamen esse non desinit substantia vel natura panis et vini. Et certe imago et similitudo corporis et sanguinis Christi in actione mysteriorum celebrantur. Jacques Paul Migne, Patrologiae Latinae, Tractatus de duabis naturis Adversus Eutychen et Nestorium 14, PL Supplementum III, Part 2:733 (Paris: Editions Garnier Freres, 1964). Edward J. Kilmartin, S.J.: According to Gelasius, the sacraments of the Eucharist communicate the grace of the principal mystery. His main concern, however, is to stress, as did Theodoret, the fact that after the consecration the elements remain what they were before the consecration. Edward J. Kilmartin, S.J., "The Eucharistic Theology of Pope Gelasius I: A Nontridentine View" in Studia Patristica, Vol. XXIX (Leuven: Peeters, 1997), p. 288. And speaking of Theodoret as Kilmartin did... Theodoret of Cyrrhus (393-466): Orth. "”You are caught in the net you have woven yourself. For even after the consecration the mystic symbols are not deprived of their own nature; they remain in their former substance figure and form; they are visible and tangible as they were before. But they are regarded as what they are become, and believed so to be, and are worshipped as being what they are believed to be. Compare then the image with the archetype, and you will see the likeness, for the type must be like the reality. For that body preserves its former form, figure, and limitation and in a word the substance of the body; but after the resurrection it has become immortal and superior to corruption; it has become worthy of a seat on the right hand; it is adored by every creature as being called the natural body of the Lord. NPNF2: Vol. III, Theodoret, Dialogue II."”The Unconfounded. Orthodoxos and Eranistes. Augustine (354-430): "They said therefore unto Him, What shall we do, that we may work the works of God?" For He had said to them, "Labor not for the meat which perisheth, but for that which endureth unto eternal life." "What shall we do?" they ask; by observing what, shall we be able to fulfill this precept? "Jesus answered and said unto them, This is the work of God, that ye believe on Him whom He has sent." This is then to eat the meat, not that which perisheth, but that which endureth unto eternal life. To what purpose dost thou make ready teeth and stomach? Believe, and thou hast eaten already. NPNF1: Vol. VII, Tractates on John, Tractate 25, §12.