Zwingli tends to be passed over quickly in world history textbooks for several reasons; the most glaring reason is the simplicity of his theology. In comparison to Luther and Calvin, both of whom wrote a stultifying amount of stuff on every topic under the sun, Zwingli stuck to a single theme throughout his arguments and writing. Still, this simple theology would form the background for the development of the more strict and radical forms of Protestantism and can still be heard in Christian churches around the globe. In fact, Zwingli's rather uncomplex theology could be described as the single most important shift in religious culture in the sixteenth century.
Zwingli's theology and morality were based on a single principle: if the Old or New Testament did not say something explicitly and literally, then no Christian should believe or practice it. This was the basis of his critique of indulgences. In 1522, for instance, Zwingli mounted a protest against the fast at Lent, a standard Catholic practice. His argument: the New Testament says absolutely nothing about fasting at Lent so the practice is inherently unchristian.
There are two important shifts in Western religious experience that result from this position. The first is the literal reading of the Old and New Testaments. No longer would these texts be dark and mysterious, full of difficult and allegorical meanings; instead, the texts of the Old and New Testaments became something like statute law. The words meant what they said; any difficulty, contradiction, or obscure meaning was the fault of the reader and not the text. Because these texts had simple and literal meanings, they also became standardized. While theologians and religious sages could debate the allegorical and figurative meanings of scriptural texts until the end of the world, the literal reading of Christian scriptures meant that it was possible to have one and only one meaning of the text. From this profound shift in the reading of the central writings of Christianity developed one of the most strict and severe applications of these writings to social life. Not only were practices not contained in Scriptures to be shunned, but practices, beliefs, and rules that were contained in the literal meaning of the Old and New Testaments were to be adhered to absolutely and uncritically. This became the underpinning of the social theories and organization of radical Protestant and Puritan societies and later the foundational social organization of the English colonies in America. We still live in a society dominated by this theory of social organization; you cannot walk down the street of American political discourse and not run into Zwinglian ideas of social organization based on the literal meaning of Christian scriptures.
While Zwingli ambitiously set out to build perhaps the strictest Protestant society, in religious, social, and moral terms, he soon parted company with Martin Luther over major doctrinal issues. Luther always had his heart rooted in Catholicism, particularly the Catholic intellectual tradition; he was not willing to give up many Catholic ceremonies and he certainly was not willing to accept Zwingli's doctrine of reading Christian scriptures with unwavering literalness. The most important doctrinal issue they disagreed on was the nature of the Eucharist. Luther, like the Catholics, believed that the bread and wine of the Eucharist was spiritually transformed into the body and blood of Christ, while Zwingli believed that the Eucharist only symbolized the body and blood of Christ. This was no mere quibble about a plain-tasting cracker and a few dribbles of wine. At the heart of the dispute was the nature of Jesus Christ himself. For Luther, what made the spiritual transformation of the Eucharist into the physical body and blood of Christ was the dual nature of Christ: as both God and human, Christ was both spiritual and physical, God and human being. Zwinglian Protestantism, as well as its spiritual inheritors (the majority of Protestant churches), overwhelmingly stressed the divine nature of Christ. Jesus Christ was the divine; the Catholic insistence on the human nature of Christ was an incorrect and dangerous reading of the Christ event in history. Therefore, any implicit suggestion in the practice of the Eucharist that Christ was human must be rejected.
Now, normally when theologians disagree, nothing much is done about it. The disagreement between Luther and Zwingli, however, was viewed as a political crisis of the highest order. As leaders of the Protestant movement in two separate countries, Luther and Zwingli threatened any kind of political alliance between the two countries. Philip of Hesse (1504-1567), the Landgrave of Hesse, understood the political benefits of an alliance with Switzerland, as did the Swiss. The Protestant states in their infancy were, after all, trying to survive beneath the cloud of Catholic Europe; the leaders of these states understood their precarious position since they were surrounded on all sides by hostile countries.
An alliance between the German and Swiss states, as intelligent as this was politically, foundered on the theological dispute between Luther and Zwingli. In order for the two states to ally themselves, the two Protestant churches had to agree on basic theology, particularly the theology of the nature of Christ.
In October 1529, Philip invited both Luther and Zwingli to his castle in Marburg to hash out their differences. The two men, however, had very little in common, and their discussions ended in failure. Luther, for his part, thought Zwingli to be mad, a religious fanatic who had lost touch with common sense and spirituality. Zwingli, for his part, thought Luther to be hopelessly enmeshed in unsupportable Catholic doctrine. In conclusion Zwingli was very important for the spread and history of the reformation because his ideas and theories spread and he revolutionised the methods used in protestant churches.
