**Transubstantiation.** — Etymologically (Lat. *trans* = beyond, *substantia* = substance), it indicates the passage of one substance into another. The official expression of the Church to denote the manner in which the real presence of the Body and Blood of Jesus Christ in the Eucharist is effected dates to the 13th century, namely the wonderful and singular conversion of the entire substance of the bread into the Body and of the entire substance of the wine into the Blood of Jesus Christ, while only the appearances of bread and wine remain unchanged (Council of Trent, sess. XIII, can. 2; Denz-U, 884).
This doctrine, implicit in the words of Jesus, “This is my Body” and “This is my Blood,” was gradually formulated, in equivalent terms, by the Fathers (transmutation, transformation, trans-elementation, etc.; *v.* EUCHARIST, III, col. 764), by ecclesiastical authors of the Carolingian age (cf. C. Gliozzo, *La dottrina della conversione eucaristica in Pascasio Radberto e Ratramno monaci di Corbia*, Palermo 1945), and by the Lateran Synod of 1079 against Berengar of Tours (*substantialiter converti*: Denz-U, 355; cf. A. Lentini, *Alberico di Montecassino nel quadro della Riforma gregoriana*, in *Studi Gregoriani*, IV, Rome 1952, pp. 55-109, esp. p. 66). Finally, in the 12th century the felicitous expression *transubstantiatio* was introduced, which was adopted in the official documents of the Church from the Fourth Lateran Council (1215) to the Council of Trent (Denz-U. 430, 465, 581, 698, 884).
It was believed that the first to use the word *transubstantiae* was Stephen of Autun, bishop of Beauçé (d. 1130 or 1140), in the *Tractatus de Sacramento Altaris*, ch. 13: “Oramus ut cibus hominum fiat cibus Angelorum, scilicet ut oblatio panis et vini transubstantietur in Corpus et Sanguinem Jesu Christi” (PL 172, 1291). However, Fr. D. Van den Eynde demonstrated (*Le tractatus de Sacramento Altaris faussement attribué à Etienne de Beauçé*, in *Recherches de théologie ancienne et médiévale*, 19 [1952], pp. 225-43) that this work is not by Stephen of Beauçé but by an author of the second half of the 12th century (perhaps another Stephen, who was bishop of Autun from about 1170 to 1189). The earliest verified attestation of this term thus remains the passage written around 1150 by Roland Bandinelli (later Pope Alexander III): “Verumtamen, si necessitate imminente, sub alterius panis specie consecraretur, profecto fieret transubstantiatio. Sanguinis autem numquam fit nisi de vino transubstantiatio” (*Sententiae*, ed. U. Gietl, Freiburg in Br. 1891, p. 231). Subsequent attestations are numerous (cf. J. De Ghellinck, *L'Eucharistie au XIIe siècle en Occident*, in *Dictionnaire de Théologie Catholique*, V, cols. 1287-1302). This term, rejected by Luther and all Protestants, yet declared by the Council of Trent to be the “most apt” expression of the Catholic dogma, was much debated within orthodox doctrine (*v.* EUCHARIST, III, cols. 764-66), though its value and precise meaning were never doubted until recent years, when attempts have been made to empty its real content by resorting to the concept of a total transformation not in a substantial sense but merely in the realm of signification (symbolic interpretation). This error was identified and rejected by Pius XII in the encyclical *Humani generis*, 12 Aug. 1950 (cf. A. Piolanti, *De symbolismo et ubiquismo eucharistico a Pio XII proscripto*, in *Euntes docete*, 4 [1951], pp. 56-71).