Transubstantiation

In Roman Catholic theology, transubstantiation means the change of the substance of bread and wine into the Body and Blood of Christ occurring in the Eucharist while all that is accessible to the senses remains as before.

Some Greek confessions use the term "transubstantiation" (in Greek, metousiosis), but most Orthodox traditions play down the term itself, and the notions of "substance" and "accidents", while still holding that the elements of bread and wine become the body and blood of Christ. Other terms such as "trans-elementation" ("metastoicheiosis") and "re-ordination" ("metarrhythmisis") are more common among the Orthodox. Most or all Protestant Reformation churches do not accept an actual change.

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 Savardin, Archbishop of Tours (died 1133), in the eleventh century and by the end of the twelfth century the term was in widespread use. In 1215, the Fourth Council of the Lateran 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."

The Council of Trent 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 thus 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. But it did not 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 "οὐσία" (Greek) or "substantia" (Latin) as the Father.