Transubstantiation (in Latin, transsubstantiatio, in Greek μετουσίωσις metousiosis) is, according to the teaching of the Catholic Church, the change of substance by which the bread and the wine offered in the sacrifice of the sacrament of the Eucharist during the Mass, become, in reality, the physical Body and Blood of Jesus the Christ. 
The Catholic Church teaches that the substance, or reality, of the Eucharistic offering (either bread alone, or bread and wine) is changed into both the Body and Blood of Christ. 
Catholics believe that, in the offering of the Eucharist, the whole presence of Christ exists in:
Transubstantiated bread, even in small fragments, and
Transubstantiated wine, even in a single drop
All that is accessible to the senses (the outward appearances – species  in Latin) remains unchanged. :1413
What remains unaltered is also referred to as the “accidents” of the bread and wine,  but the term “accidents” is not used in the official definition of the doctrine by the Council of Trent.  The manner in which the change occurs, the Catholic Church teaches, is a mystery: “The signs of bread and wine become, in a way surpassing understanding, the Body and Blood of Christ.” :1333
The Eastern Orthodox Church, Oriental Orthodox Church, and Church of the East have sometimes used the term “transubstantiation” (metousiosis); however, terms such as “divine mystery”, “trans-elementation” (μεταστοιχείωσις metastoicheiosis), “re-ordination” (μεταρρύθμισις metarrhythmisis), or simply “change” (μεταβολή) are more common among them, and they consider the Eucharist with its change from bread and wine to the body and blood of Christ a “Mystery”. Eastern Catholic Churches in communion with the Holy See likewise prefer such terms and see them alongside the teaching expressed by the term “transubstantiation”, which likewise denotes an actual change, a “becoming”, as opposed to the mere addition of a new symbolic significance expressed in “to be for us the body and blood of Christ”. 
The earliest known use of the term “transubstantiation” to describe the change from bread and wine to body and blood of Christ in the Eucharist was by Hildebert de Lavardin, Archbishop of Tours, in the 11th century.  By the end of the 12th century the term was in widespread use.  The Fourth Council of the Lateran, which convened beginning November 11, 1215,  spoke of the bread and wine as “transubstantiated” into the body and blood of Christ: “His body and blood are truly contained in the sacrament of the altar under the forms of bread and wine, the bread and wine having been transubstantiated, by God’s power, into his body and blood”. 
During the Protestant Reformation, the doctrine of transubstantiation was heavily criticised as an Aristotelian “pseudophilosophy”  imported into Christian teaching and jettisoned in favor of Martin Luther’s doctrine of sacramental union, or in favor, per Huldrych Zwingli, of the Eucharist as memorial. 
The Council of Trent in its 13th session ending October 11, 1551, defined transubstantiation as “that wonderful and singular conversion of the whole substance of the bread into the Body, and of the whole substance of the wine into the Blood – the species only of the bread and wine remaining – which conversion indeed the Catholic Church most aptly calls Transubstantiation”. 
This council officially approved use of the term “transubstantiation” to express the Catholic Church’s teaching on the subject of the conversion of the bread and wine into the body and blood of Christ in the Eucharist, with the aim of safeguarding Christ’s presence as a literal truth, while emphasizing the fact that there is no change in the empirical appearances of the bread and wine.  It did not however impose the Aristotelian theory of substance and accidents: it spoke only of the species (the appearances), not the philosophical term “accidents”, and the word “substance” was in ecclesiastical use for many centuries before Aristotelian philosophy was adopted in the West, 
as shown for instance by its use in the Nicene Creed which speaks of Christ having the same “ο σία” (Greek) or “substantia” (Latin) as the Father.
The belief that the Eucharist conveyed to the believer the body and blood of Christ appears to have been widespread from an early date, and the elements were commonly referred to as the body and the blood by early Christian writers. The early Christians who use these terms also speak of it as the flesh and blood of Christ, the same flesh and blood which suffered and died on the cross.
The short document known as the Teaching of the Apostles or Didache, which may be the earliest Christian document outside of the New Testament to speak of the Eucharist, says, “Let no one eat or drink of the Eucharist with you except those who have been baptized in the Name of the Lord,”  for it was in reference to this that the Lord said, “Do not give that which is holy to dogs.” Matthew 7:6
A letter by Saint Ignatius of Antioch to the Romans, written in AD 106 says: “I desire the bread of God, which is the flesh of Jesus Christ.” 
Writing to the Christians of Smyrna, in about AD 106, Saint Ignatius warned them to “stand aloof from such heretics”, because, among other reasons, “they abstain from the Eucharist and from prayer, because they confess not the Eucharist to be the flesh of our Savior Jesus Christ, which suffered for our sins, and which the Father, of His goodness, raised up again.” 
In about 150, Justin Martyr wrote that the Eucharist is “Not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Savior, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh.” 
Justin Martyr wrote, in Dialogue with Trypho, ch 70: “Now it is evident, that in this prophecy to the bread which our Christ gave us to eat, in remembrance of His being made flesh for the sake of His believers, for whom also He suffered; and to the cup which He gave us to drink, in remembrance of His own blood, with giving of thanks.”
In about 200 AD, Tertullian wrote (Against Marcion IV. 40): “Taking bread and distributing it to his disciples he made it his own body by saying, ‘This is my body,’ that is a ‘figure of my body.’ On the other hand, there would not have been a figure unless there was a true body.”
The Apostolic Constitutions (compiled c. 380) says: “Let the bishop give the oblation, saying, The body of Christ; and let him that receiveth say, Amen. And let the deacon take the cup; and when he gives it, say, The blood of Christ, the cup of life; and let him that drinketh say, Amen.” 
Saint Ambrose of Milan (d. 397) wrote:
Perhaps you will say, “I see something else, how is it that you assert that I receive the Body of Christ?” … Let us prove that this is not what nature made, but what the blessing consecrated, and the power of blessing is greater than that of nature, because by blessing nature itself is changed. … For that sacrament which you receive is made what it is by the word of Christ. But if the word of Elijah had such power as to bring down fire from heaven, shall not the word of Christ have power to change the nature of the elements? … Why do you seek the order of nature in the Body of Christ, seeing that the Lord Jesus Himself was born of a Virgin, not according to nature? It is the true Flesh of Christ which was crucified and buried, this is then truly the Sacrament of His Body. The Lord Jesus Himself proclaims: “This Is My Body.” Before the blessing of the heavenly words another nature is spoken of, after the consecration the Body is signified. He Himself speaks of His Blood. Before the consecration it has another name, after it is called Blood. And you say, Amen, that is, It is true. Let the heart within confess what the mouth utters, let the soul feel what the voice speaks.” 
Other fourth-century Christian writers say that in the Eucharist there occurs a “change”,  “transelementation”, 
“transformation”,  “transposing”, 
“alteration”  of the bread into the body of Christ.
In AD 400, Augustine quotes Cyprian (AD 200): “For as Christ says ‘I am the true vine,’ it follows that the blood of Christ is wine, not water; and the cup cannot appear to contain His blood by which we are redeemed and quickened, if the wine be absent; for by the wine is the blood of Christ typified, …” 
In the eleventh century, Berengar of Tours denied that any material change in the elements was needed to explain the Eucharistic Presence, thereby provoking a considerable stir. 
Berengar’s position was never diametrically opposed to that of his critics, and he was probably never excommunicated, but the controversy that he aroused forced people to clarify the doctrine of the Eucharist. 
The earliest known use of the term “transubstantiation” to describe the change from bread and wine to body and blood of Christ was by Hildebert de Lavardin, Archbishop of Tours (died 1133), in about 1079,  long before the Latin West, under the influence especially of Thomas Aquinas (c. 1227-1274), accepted Aristotelianism.
Although it was only in the West that Aristotelian philosophy prevailed,  the objective reality of the Eucharistic change in a valid Divine liturgy is also believed in by the Eastern Orthodox Church and the other ancient Churches of the East (see metousiosis).
In 1215, the Fourth Lateran Council used the word transubstantiated in its profession of faith, when speaking of the change that takes place in the Eucharist. It was only later in the 13th century that Aristotelian metaphysics was accepted and a philosophical elaboration in line with that metaphysics was developed, which found classic formulation in the teaching of Saint Thomas Aquinas.” 
In 1551, the Council of Trent officially defined, with a minimum of technical philosophical language,  that “by the consecration of the bread and wine there takes place a change of the whole substance of the bread into the substance of the body of Christ our Lord and of the whole substance of the wine into the substance of his blood. This change the holy Catholic Church has fittingly and properly called transubstantiation.” 
Title page of Martin Luther’s De Captivitate Babylonica Ecclesiae
In the Protestant Reformation, the doctrine of transubstantiation became a matter of much controversy. Martin Luther held that “It is not the doctrine of transubstantiation which is to be believed, but simply that Christ really is present at the Eucharist”.  In his “On the Babylonian Captivity of the Church” (published on 6 October 1520) Luther wrote:
Therefore it is an absurd and unheard-of juggling with words, to understand “bread” to mean “the form, or accidents of bread,” and “wine” to mean “the form, or accidents of wine.” Why do they not also understand all other things to mean their forms, or accidents? Even if this might be done with all other things, it would yet not be right thus to emasculate the words of God and arbitrarily to empty them of their meaning. Moreover, the Church had the true faith for more than twelve hundred years, during which time the holy Fathers never once mentioned this transubstantiation — certainly, a monstrous word for a monstrous idea — until the pseudo-philosophy of Aristotle became rampant in the Church these last three hundred years. During these centuries many other things have been wrongly defined, for example, that the Divine essence neither is begotten nor begets, that the soul is the substantial form of the human body, and the like assertions, which are made without reason or sense, as the Cardinal of Cambray himself admits. 
In his 1528 Confession Concerning Christ’s Supper he wrote:
Why then should we not much more say in the Supper, “This is my body”, even though bread and body are two distinct substances, and the word “this” indicates the bread? Here, too, out of two kinds of objects a union has taken place, which I shall call a “sacramental union”, because Christ’s body and the bread are given to us as a sacrament. This is not a natural or personal union, as is the case with God and Christ. It is also perhaps a different union from that which the dove has with the Holy Spirit, and the flame with the angel, but it is also assuredly a sacramental union. 
What Luther thus called a “sacramental union” is often erroneously called consubstantiation by non-Lutherans.
In “On the Babylonian Captivity”, Luther upheld belief in the Real Presence of Jesus and, in his 1523 treatise The Adoration of the Sacrament, defended adoration of the body and blood of Christ in the Eucharist.
Huldrych Zwingli taught that the sacrament is purely symbolic and memorial in character, arguing that this was the meaning of Jesus’ instruction: “Do this in remembrance of me”. 
The 39 articles of religion in the Church of England declare: “Transubstantiation (or the change of the substance of Bread and Wine) in the Supper of the Lord, cannot be proved by holy Writ; but is repugnant to the plain words of Scripture, overthroweth the nature of a Sacrament, and hath given occasion to many superstitions”;  and made Mass illegal.
19:12 His eyes were as a flame of fire, and on his head were many crowns; and he had a name written, that no man knew, but he himself.19:13 And he was clothed with a vesture dipped in blood: and his name is called The Word of God.19:14 And the armies which were in heaven followed him upon white horses, clothed in fine linen, white and clean.19:15 And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God.19:16 And he hath on his vesture and on his thigh a name written, KING OF KINGS, AND LORD OF LORDS.19:17 And I saw an angel standing in the sun; and he cried with a loud voice, saying to all the fowls that fly in the midst of heaven, Come and gather yourselves together unto the supper of the great God;19:18 That ye may eat the flesh of kings, and the flesh of captains, and the flesh of mighty men, and the flesh of horses, and of them that sit on them, and the flesh of all men, both free and bond, both small and great.19:19 And I saw the beast, and the kings of the earth, and their armies, gathered together to make war against him that sat on the horse, and against his army.19:20 And the beast was taken, and with him the false prophet that wrought miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone.19:21 And the remnant were slain with the sword of him that sat upon the horse, which sword proceeded out of his mouth: and all the fowls were filled with their flesh. Revelation
As is noted above, the canonical hours stemmed from Jewish prayer. During the Babylonian Exile, when the Temple was no longer in use, the first synagogues were established, and the services (at fixed hours of the day) of Torah readings, psalms, and hymns began to evolve. This “sacrifice of praise” began to be substituted for the sacrifices of animals.
By the time of the Roman Empire, the Jews (and eventually early Christians) began to follow the Roman system of conducting the business day in scheduling their times for prayer  . In Roman cities, the bell in the forum rang the beginning of the business day at about six o’clock in the morning (Prime, the “first hour”), noted the day’s progress by striking again at about nine o’clock in the morning (Terce, the “third hour”), tolled for the lunch break at noon (Sext, the “sixth hour”), called the people back to work again at about three o’clock in the afternoon (None, the “ninth hour”), and rang the close of the business day at about six o’clock in the evening (the time for evening prayer).
The first miracle attributed to the Apostles, the healing of the crippled man on the temple steps, occurred because Peter and John went to the Temple to pray (Acts 3:1 ). This was at the “ninth hour” of prayer (about 3 pm), the time at which the “evening” sacrifice was celebrated in the Temple in the New Testament [Second Temple] period. One of the defining moments of the early Church, the decision to include Gentiles among the community of believers, arose from a vision Peter had while praying at noontime (Acts 10:9–49 ). This was at the “sixth hour,” the time of the Mussaf prayers associated with additional sacrifices in the Temple on special days.
As Christianity began to separate from Judaism, the practice of praying at fixed times continued. The early church was known to pray the Psalms (Acts 4:23–30 ), which has remained a part of the canonical hours and all Christian prayer since. By 60 AD, the Didache, the oldest known liturgical manual for Christians, recommended disciples to pray the Lord’s Prayer three times a day; this practice found its way into the canonical hours as well. Pliny the Younger (63 – ca. 113), who was not a Christian himself, mentions not only fixed times of prayer by believers, but also specific services—other than the Eucharist—assigned to those times: “they met on a stated day before it was light, and addressed a form of prayer to Christ, as to a divinity … after which it was their custom to separate, and then reassemble, to eat in common a harmless meal. .” 
By the second and third centuries, such Church Fathers as Clement of Alexandria, Origen, and Tertullian wrote of the practice of Morning and Evening Prayer, and of the prayers at terce, sext, and none. The prayers could be prayed individually or in groups. By the third century, the Desert Fathers (the earliest monks), began to live out St. Paul’s command to “pray without ceasing” (I_Thessalonians 5:17 ) by having one group of monks pray one fixed-hour prayer while having another group pray the next prayer.
As the format of unbroken fixed-hour prayer developed in the Christian monastic communities in the East and West, longer prayers soon grew, but the cycle of prayer became the norm in daily life in monasteries. By the fourth century, the characteristics of the canonical hours more or less took their present shape. For secular (non-monastic) clergymen and lay people, the fixed-hour prayers were by necessity much shorter. In many churches and basilicas staffed by monks, the form of the fixed-hour prayers was a hybrid of secular and monastic practice.
In the East, the development of the Divine Services shifted from the area around Jerusalem to Constantinople. In particular, St. Theodore the Studite (ca. 758 – ca. 826) combined a number of influences from the Byzantine court ritual with monastic practices common in Asia Minor, and added thereto a number of hymns composed by himself and his brother Joseph (see Typicon for further details).
In the West, St. Benedict in his famous Rule modeled his guidelines for the prayers on the customs of the basilicas of Rome. It was he who expounded the concept in Christian prayer of the inseparability of the spiritual life from the physical life. The Benedictines began to call the prayers the Opus Dei or “Work of God.”
As the Divine Office grew more important in the life of the Church, the rituals became more elaborate. Soon, praying the Office began to require various books, such as a psalter for the psalms, a lectionary to find the assigned Scripture reading for the day, a Bible to proclaim the reading, a hymnal for singing, etc. As parishes grew in the Middle Ages away from cathedrals and basilicas, a more concise way of arranging the hours was needed. So, a sort of list developed called the Breviary, which gave the format of the daily office and the texts to be used.
The spread of breviaries eventually reached Rome, where Pope Innocent III extended its use to the Roman Curia. The Franciscans sought a one-volume breviary for its friars to use during travels, so the order adopted the Breviarium Curiae, but substituting the Gallican Psalter for the Roman. The Franciscans gradually spread this breviary throughout Europe. Pope Nicholas III would then adopt the widely used Franciscan breviary to be the breviary used in Rome. By the 14th century, the breviary