The idea that God’s own words, found in the Bible, should be the key standard and test of faith was one that many fifteenth-century reformers could endorse. It was not much different from the idea of seeking out an authoritative ancient Roman treatise on rhetoric, like Cicero’s The Orator (55 BCE), and using that as the guide for how to write and speak persuasively. There was a simple elegance in going directly to the source, and a real scholarly incentive to find the most accurate version. Some religious reformers took this drive “to the sources” (ad fontes) a step further and argued that the Bible as God’s Word should be the only standard and test of faith, bypassing centuries of theological reflection and ecclesiastical rule making. The principle of “Scripture Alone” is credited to Martin Luther, but here his Swiss contemporary Ulrich Zwingli (1484–1531) articulates the same position. Both rejected large parts of Catholic theology and tradition on the basis of this principle, which became a key point of identity for many Protestants. While Luther and Zwingli both held that Scripture was clear and transparent, they argued bitterly over how to interpret Christ’s words on the meaning of the Eucharist, or communion. 1