The real beginning of the Reformation in Switzerland was Zwingli's lectures on the New Testament in 1519. Armed with Erasmus' 1516 edition of the Greek text he discarded scholastic commentaries and proclaimed the sole authority of the word of God as revealed in Scriptures. With his expression of opposition to Lenten observances in 1522 the Reformation in Zürich was well under way. In the same year, with the publication of Architeles, he made clear his belief in freedom from the control of the Roman hierarchy. A public disputation with a papal representative was held before the general council at Zürich in 1523; Zwingli presented his doctrines in 67 theses. The council approved the Zwinglian position and instructed all priests in the canton to comply.
The new practices were rapidly put into effect—organs were destroyed, images were removed from churches, priests were allowed to marry, monasticism was abolished, the liturgy was simplified, and the sacrament of communion reduced to a commemorative feast. In 1524, Zwingli publicly celebrated his marriage, which he had illegally contracted two years previously. In 1525 the Catholic Mass was replaced by a reformed service at Zwingli's church in Zürich.
Zwingli became embroiled with the Lutherans in a doctrinal dispute concerning the nature of the Eucharist (see Lord's Supper). Philip of Hesse endeavored to reconcile these differences within the Protestant ranks by calling the disputants together at the Marburg Colloquy (1529). Zwingli and Johannes Oecolampadius and Luther and Philip Melanchthon were present, but no agreement was reached.
Although Bern adopted Zwingli's reforms in 1528, and Basel and St. Gall soon after, he faced agitation by the Anabaptists, who wanted even more radical reform, and the armed resistance of the Forest Cantons that had remained loyal to Rome. When Zürich imposed a trade embargo on these cantons they retaliated with war (1531), and at the battle of Kappel, Zwingli was killed. Zwingli's work in Zürich was carried on by his colleague and son-in-law, Heinrich Bullinger, but the Reformation in Switzerland passed into the hands of John Calvin. Calvin built his comprehensive theological system partly on the groundwork laid by Zwingli, but he resisted Zwingli's more radical teaching on baptism and the Lord's Supper. The Consensus Tigurinus (1549) marks the departure of the Swiss Reformation from Zwinglian to Calvinist doctrine.