Becoming the Body and Blood
We have not noted it much in our analysis of the Lutheran Confessions, but there are significant differences sometimes between the German and Latin versions of the Augsburg Confession. The Latin version is what was read at the Diet of Augsburg. The differences matter in Article X because the German utilizes the language that the Fourth Lateran Council (1215) to define the sort of presence the body and blood of Christ enjoin in the Supper. This language is "the true body and blood of Christ are truly present under the form of the bread and wine." This deserves consideration.
The Reformers took many different paths to the practice and understanding of the Supper, paths that differed so much that there was no way in which the Lutherans and others could confess together on this view. The Marburg articles, for instance, lie in the history before the Augsburg Confession, and there was attempted a meeting to reconcile all the parties and concerns. We will have to wait until we get to the Formula of Concord to discuss inter-Reformation disputes and the way in which a consensus has been formed since the time of the Reformation.
Luther's most notorious statements (and probably his most fair statements) on Transsubstantiation occur in the Babylonian Captivity of the Church (1521). There are three forms of captivity facing the Sacrament of the Altar and one of them is the dogmatic necessity of a) the theory of transsubstantiation and b) calling it that. Luther at that time understood the main offense to be the necessity of believing one particular theory over all the rest. Later, he would find other objections to add.
Transsubstantiation sometimes is understood as a crude set of beliefs. Rather, it was a very sophisticated response developed to counter very crass sorts of language about the Supper that were popular and widespread in the church. This view was expressed by a confession known as I, Berengar. Berengar was a monk who was investigating theories of presence and countered the common belief. He was forced to recant his views and instead express that "...the body of Christ is truly crushed by the teeth [of the communicant]... ." A few generations later, theologians saw much danger in these views and their work helped to convene the Fourth Lateran Council at which transsubstantiation was defined. However, at this time, transsubstantiation was understood in a variety of ways. The view known as conssubstantiation, that the bread and wine coextend with Christ's body and blood, also was a legitimate interpretation of the dogma.
That all changed when Thomas Aquinas came onto the scene. His polemics worked to delimite the scope of legitimate understandings of the dogma and thereby secured the theory that we know as transsubstantiation. He considers other theories heretical.
It is the great merit of Article X of the Augsburg Confession that it can contain within it interpretation of Christ's presence such as that of Thomas' or the variety of views that existed at the time of the Fourth Lateran Council. This article remains silent about the true 'how' of it all, namely the manner of the change. It is to be lamented that Trent asserts the necessity of an understanding of this change with the force of an anathema.