bread and wine were his body and blood must be taken literally, since God is truth. He thus believes that the change of the substances of the bread and wine into the body and blood of Christ offered in the Eucharist really occurs. Only if the Eucharist is the actual body and blood of Christ can a Christian know it is salvific. In the 11th century, Berengar of Tours stirred up opposition when he denied that any material change in the elements was needed to explain the fact of the Real Presence. His position was never diametrically opposed to that of his critics, and he was probably never excommunicated, but the controversies that he aroused (see Stercoranism) 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 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 in 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". Catholic scholars and clergy have noted numerous reports of Eucharistic miracles contemporary with the council, and at least one such report was discussed at the council. It was not until 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 Thomas Aquinas" and in the theories of later Catholic theologians in the medieval period (saint Robert Grosseteste, the Augustinian Giles of Rome and the Franciscans Duns Scotus and William of Ockham) and beyond.<ref>[http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1126&context=classicsfacpub Stephen E. Lahey, "Review of Adams, Some later medieval theories ..." in The Journal of Ecclesiastical History, vol. 63, issue 1 (January 2012)]</ref> Reformation 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. In the Protestant Reformation, the doctrine of transubstantiation became