In fact, the early Fathers took the transubstantiation for granted. Here are excerpts from an article regarding transubstantiation and the early Fathers:
Source:
therealpresence.org/eucharst/father/a5.html
"Thus, I decided to research what the Early Christians believed on this issue.
I searched the indices for “Eucharist” in many volume sets on Early Christian writings, and I was astonished at my discovery. The Early Christians actually took the Real Presence for granted. It doesn’t even seem as if there was much debate.
I could not find anyone who denied the Real Presence of Our Lord in the Blessed Sacrament before the year 500 A.D."
**ST. IGNATIUS OF ANTIOCH: ** “Consider how contrary to the mind of God are the heterodox in regard to the grace of God which has come to us. They have no regard for charity, none for the widow, the orphan, the oppressed, none for the man in prison, the hungry or the thirsty.
They abstain from the Eucharist and from prayer, because they do not admit that the Eucharist is the flesh of our Savior Jesus Christ, the flesh which suffered for our sins and which the Father, in His graciousness, raised from the dead.” “Letter to the Smyrnaeans”, paragraph 6. circa 80-110 A.D.
ST. IGNATIUS OF ANTIOCH: “I have no taste for the food that perishes nor for the pleasures of this life.
I want the Bread of God which is the Flesh of Christ, who was the seed of David; and for drink I desire His Blood which is love that cannot be destroyed.” -“Letter to the Romans”, paragraph 7, circa 80-110 A.D.
ST. IGNATIUS OF ANTIOCH: “Take care, then who belong to God and to Jesus Christ - they are with the bishop. And those who repent and come to the unity of the Church - they too shall be of God, and will be living according to Jesus Christ. Do not err, my brethren: if anyone follow a schismatic, he will not inherit the Kingdom of God. If any man walk about with strange doctrine, he cannot lie down with the passion.
Take care, then, to use one Eucharist, so that whatever you do, you do according to God: for there is one Flesh of our Lord Jesus Christ, and one cup in the union of His Blood; one altar, as there is one bishop with the presbytery and my fellow servants, the deacons.” -Epistle to the Philadelphians, 3:2-4:1, 110 A.D.
ST. JUSTIN MARTYR: “This food we call the Eucharist, of which no one is allowed to partake except one who believes that the things we teach are true, and has received the washing for forgiveness of sins and for rebirth, and who lives as Christ handed down to us. For we do not receive these things as common bread or common drink; but as Jesus Christ our Savior being incarnate by God’s Word took flesh and blood for our salvation, so also we have been taught that the food consecrated by the Word of prayer which comes from him, from which our flesh and blood are nourished by transformation, is the flesh and blood of that incarnate Jesus.” " First Apology", Ch. 66, inter A.D. 148-155
ST. IRENAEUS OF LYON: [Christ] has declared the cup, a part of creation,
to be his own Blood, from which he causes our blood to flow;
and the bread, a part of creation, he has established as his own Body, from which he gives increase to our bodies." Source: St. Irenaeus of Lyons, Against Heresies, 180 A.D.:
ST. IRENAEUS OF LYON: So then, if the mixed cup and the manufactured bread receive the Word of God and become the Eucharist, that is to say, the Blood and Body of Christ, which fortify and build up the substance of our flesh, how can these people claim that the flesh is incapable of receiving God’s gift of eternal life, when it is nourished by Christ’s Blood and Body and is His member? As the blessed apostle says in his letter to the Ephesians, ‘For we are members of His Body, of His flesh and of His bones’ (Eph. 5:30). He is not talking about some kind of ‘spiritual’ and ‘invisible’ man, ‘for a spirit does not have flesh an bones’ (Lk. 24:39). No, he is talking of the organism possessed by a real human being, composed of flesh and nerves and bones. It is this which is nourished by the cup which is His Blood, and is fortified by the bread which is His Body. The stem of the vine takes root in the earth and eventually bears fruit, and ‘the grain of wheat falls into the earth’ (Jn. 12:24), dissolves, rises again, multiplied by the all-containing Spirit of God, and finally after skilled processing, is put to human use. These two then receive the Word of God and become the Eucharist, which is the Body and Blood of Christ."
Please read the entire article to learn the “truth” of transubstantiation and the early Fathers.