The most important early reformer other than Luther was the Swiss humanist, priest, and admirer of Erasmus, Ulrich Zwingli (ZWIHNG-lee) (1484–1531). Zwingli announced in 1519 that he would not preach from the church’s prescribed readings but, relying on Erasmus’s New Testament, go right through the New Testament “from A to Z,” that is, from Matthew to Revelation. Zwingli was convinced that Christian life rested on the Scriptures, which were the pure words of God and the sole basis of religious truth. He went on to attack indulgences, the Mass, the institution of monasticism, and clerical celibacy. In his gradual reform of the church in Zurich, he had the strong support of the city authorities, who had long resented the privileges of the clergy.

The followers of Luther, Zwingli, and others who called for a break with Rome came to be called Protestants. The word Protestant derives from the protest drawn up by a small group of reforming German princes at the Diet of Speyer in 1529. The princes “protested” the decisions of the Catholic majority, and the word gradually became a general term applied to all non-Catholic western European Christians.

Luther, Zwingli, and other early Protestants agreed on many things. First, how is a person to be saved? Traditional Catholic teaching held that salvation is achieved by both faith and good works. Protestants held that salvation comes by faith alone, irrespective of good works or the sacraments. God, not people, initiates salvation. (See “Primary Source 13.1: Martin Luther, On Christian Liberty.”) Second, where does religious authority reside? Christian doctrine had long maintained that authority rests both in the Bible and in the traditional teaching of the church. For Protestants, authority rested in the Bible alone. For a doctrine or issue to be valid, it had to have a scriptural basis. Because of this, most Protestants rejected Catholic teachings about the sacraments — the rituals that the church had defined as imparting God’s benefits on the believer — holding that only baptism and the Eucharist have scriptural support.

Third, what is the church? Protestants held that the church is a spiritual priesthood of all believers, an invisible fellowship not fixed in any place or person, which differed markedly from the Roman Catholic practice of a hierarchical clerical institution headed by the pope in Rome. Fourth, what is the highest form of Christian life? The medieval church had stressed the superiority of the monastic and religious life over the secular. Protestants disagreed and argued that every person should serve God in his or her individual calling.

Protestants did not agree on everything, and one important area of dispute was the ritual of the Eucharist (also called communion, the Lord’s Supper, and, in Catholicism, the Mass). Catholicism holds the dogma of transubstantiation: by the consecrating words of the priest during the Mass, the bread and wine become the actual body and blood of Christ. In opposition, Luther believed that Christ is really present in the consecrated bread and wine, but this is the result of God’s mystery, not the actions of a priest. Zwingli understood the Eucharist as a memorial in which Christ was present in spirit among the faithful, but not in the bread and wine. The Colloquy of Marburg, summoned in 1529 to unite Protestants, failed to resolve these differences, though Protestants reached agreement on almost everything else.