By a great Catholic[1] he has been called "the glory of the priesthood and the shame," by an eminent Protestant scholar[2] "a John the Baptist and Judas in one." [Sidenote: Sacramentarian schism] The battle with the humanists was synchronous with the beginnings of a fierce internecine strife that tore the young evangelical church into two parts.

Though the controversy between Luther and his principal rival, Ulrich Zwingli, was really caused by a wide difference of thought on many subjects, it focused its rays, like a burning-glass, upon one point, the doctrine of the real presence of the body and blood of Christ in the {108} eucharist.

The explanation of this mystery evolved in the Middle Ages and adopted by the Lateran Council of 1215, was the theory, called "transubstantiation," that the substance of the bread turned into the substance of the body, and the substance of the wine into the substance of the blood, without the "accidents" of appearance and taste being altered.

Some of the later doctors of the church, Durand and Occam, opposed this theory, though they proposed a nearly allied one, called "consubstantiation," that the body and blood are present with the bread and wine.

Wyclif and others, among whom was the Italian philosopher Pico della Mirandola, proposed the theory now held in most Protestant churches that the bread and wine are mere symbols of the body and blood.
At the dawn of the Reformation the matter was brought into prominence by the Dutch theologian Hoen, from whom the symbolic interpretation [Sidenote: Symbolism] was adopted first by Carlstadt and then by the Swiss Reformers Zwingli and Oecolampadius.