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As indicated, Church councils resolve aand state in detail church doctrine when there has been some contrary viewpoints. The Church goes back to the Apostles and early church leaders to establish what was taught and practiced. As you can see, many of the early church leaders wrote about the Real Presence and was clearly mentioned in the Bible in several areas. Transubstantiation was defined later and affirmed at the council of Lateran IV in 1215.

Councils are legally convened assemblies of ecclesiastical dignitaries and theological experts for the purpose of discussing and regulating matters of church doctrine and discipline. The terms council and synod are synonymous, although in the oldest Christian literature the ordinary meetings for worship are also called synods,

Twelfth Ecumenical Council: Lateran IV (1215)
The Fourth Lateran Council was held under Innocent III. There were present the Patriarchs of Constantinople and Jerusalem, 71 archbishops, 412 bishops, and 800 abbots the Primate of the Maronites, and St. Dominic. It issued an enlarged creed (symbol) against the Albigenses (Firmiter credimus), condemned the Trinitarian errors of Abbot Joachim, and published 70 important reformatory decrees. This is the most important council of the Middle Ages, and it marks the culminating point of ecclesiastical life and papal power.

•Canon 1: Exposition of the Catholic Faith and of the dogma of Transubstantiation

For we have the two extremes of conversion, namely, bread and wine as the terminus a quo, and the Body and Blood of Christ as the terminus ad quem. Furthermore, the intimate connection between the cessation of one extreme and the appearance of the other seems to be preserved by the fact, that both events are the results, not of two independent processes, as, e.g. annihilation and creation, but of one single act, since, according to the purpose of the Almighty, the substance of the bread and wine departs in order to make room for the Body and Blood of Christ. Lastly, we have the commune tertium in the unchanged appearances of bread and wine, under which appearances the pre-existent Christ assumes a new, sacramental mode of being, and without which His Body and Blood could not be partaken of by men. That the consequence of Transubstantiation, as a conversion of the total substance, is the transition of the entire substance of the bread and wine into the Body and Blood of Christ, is the express doctrine of the Church (Council of Trent, Sess. XIII, can. ii).

For details: http://www.newadvent.org/cathen/05573a.htm#section3

Early fathers on the Real Presence of Jesus in the Eucharist:

St. Ignatius of Antioch (110 A.D.)
I have no taste for corruptible food nor for the pleasures of this life. I desire the Bread of God, WHICH IS THE FLESH OF JESUS CHRIST, who was of the seed of David; and for drink I DESIRE HIS BLOOD, which is love incorruptible. (Letter to the Romans 7:3)
St. Justin the Martyr (100 - 165 A.D.)
We call this food Eucharist; and no one else is permitted to partake of it, except one who believes our teaching to be true and who has been washed in the washing which is for the remission of sins and for regeneration [Baptism], and is thereby living as Christ has enjoined

For not as common bread nor common drink do we receive these; but since Jesus Christ our Savior was made incarnate by the word of God and had both flesh and blood for our salvation, so too, as we have been taught, the food which has been made into the Eucharist by the Eucharistic prayer set down by Him, AND BY THE CHANGE OF WHICH our blood and flesh is nourished, IS BOTH THE FLESH AND THE BLOOD OF THAT INCARNATED JESUS. (First Apology, 66)

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… (Letter to the Philadelphians 4:1

St. Irenaeus of Lyons (140 - 202 A.D.)
…He took from among creation that which is bread, and gave thanks, saying, “THIS IS MY BODY.” The cup likewise, which is from among the creation to which we belong, HE CONFESSED TO BE HIS BLOOD.

He taught THE NEW SACRIFICE OF THE NEW COVENANT, of which Malachi, one of the twelve prophets, had signified beforehand: [quotes Mal 1:10-11]. By these words He makes it plain that the former people will cease to make offerings to God; BUT THAT IN EVERY PLACE SACRIFICE WILL BE OFFERED TO HIM, and indeed, a pure one

http://www.catholicbible101.com/transubstantiation.htm

Another source: http://www.justforcatholics.org/a181.htm

From http://en.wikipedia.org/wiki/Paschasius_Radbertus

The most well-known and influential work of St. Paschasius, De Corpore et Sanguine Domini (written between 831 and 833), is an exposition on the nature of the Eucharist. It was originally written as an instructional manual for the monks under his care at Corbie, and is the first lengthy treatise on the sacrament of the Eucharist in the Western world.[4] In it, Paschasius agrees with Ambrose in affirming that the Eucharist contains the true, historical body of Jesus Christ. According to Paschasius, God is truth itself, and therefore, his words and actions must be true.

Shortly thereafter, a third monk joined the debate, Rabanus Maurus, which initiated the Carolingian Eucharist Controversy.[9] Ultimately, however, the king accepted Paschasius’ assertion, and the physical presence of Christ in the Eucharist became the dominant belief in the Roman Catholic faith.

Peace be with you.